SCREEN(1)SCREEN(1)NAMEscreen - screen manager with VT100/ANSI terminal emulation
SYNOPSISscreen [ -options ] [ cmd [ args ] ]
screen-r [[pid.]tty[.host]]
screen-r sessionowner/[[pid.]tty[.host]]
DESCRIPTION
Screen is a full-screen window manager that multiplexes a
physical terminal between several processes (typically
interactive shells). Each virtual terminal provides the
functions of a DEC VT100 terminal and, in addition, sev-
eral control functions from the ISO 6429 (ECMA 48, ANSI
X3.64) and ISO 2022 standards (e.g. insert/delete line and
support for multiple character sets). There is a scroll-
back history buffer for each virtual terminal and a copy-
and-paste mechanism that allows moving text regions
between windows.
When screen is called, it creates a single window with a
shell in it (or the specified command) and then gets out
of your way so that you can use the program as you nor-
mally would. Then, at any time, you can create new (full-
screen) windows with other programs in them (including
more shells), kill existing windows, view a list of win-
dows, turn output logging on and off, copy-and-paste text
between windows, view the scrollback history, switch
between windows in whatever manner you wish, etc. All win-
dows run their programs completely independent of each
other. Programs continue to run when their window is cur-
rently not visible and even when the whole screen session
is detached from the user's terminal. When a program ter-
minates, screen (per default) kills the window that con-
tained it. If this window was in the foreground, the dis-
play switches to the previous window; if none are left,
screen exits.
Everything you type is sent to the program running in the
current window. The only exception to this is the one
keystroke that is used to initiate a command to the window
manager. By default, each command begins with a control-a
(abbreviated C-a from now on), and is followed by one
other keystroke. The command character and all the key
bindings can be fully customized to be anything you like,
though they are always two characters in length.
Screen does not understand the prefix "C-" to mean con-
trol. Please use the caret notation ("^A" instead of "C-
a") as arguments to e.g. the escape command or the -e
option. Screen will also print out control characters in
caret notation.
The standard way to create a new window is to type "C-a
c". This creates a new window running a shell and
switches to that window immediately, regardless of the
state of the process running in the current window. Simi-
larly, you can create a new window with a custom command
in it by first binding the command to a keystroke (in your
.screenrc file or at the "C-a :" command line) and then
using it just like the "C-a c" command. In addition, new
windows can be created by running a command like:
screen emacs prog.c
from a shell prompt within a previously created window.
This will not run another copy of screen, but will instead
supply the command name and its arguments to the window
manager (specified in the $STY environment variable) who
will use it to create the new window. The above example
would start the emacs editor (editing prog.c) and switch
to its window.
If "/etc/utmp" is writable by screen, an appropriate
record will be written to this file for each window, and
removed when the window is terminated. This is useful for
working with "talk", "script", "shutdown", "rsend", "sccs"
and other similar programs that use the utmp file to
determine who you are. As long as screen is active on your
terminal, the terminal's own record is removed from the
utmp file. See also "C-a L".
GETTING STARTED
Before you begin to use screen you'll need to make sure
you have correctly selected your terminal type, just as
you would for any other termcap/terminfo program. (You
can do this by using tset for example.)
If you're impatient and want to get started without doing
a lot more reading, you should remember this one command:
"C-a ?". Typing these two characters will display a list
of the available screen commands and their bindings. Each
keystroke is discussed in the section "DEFAULT KEY BIND-
INGS". The manual section "CUSTOMIZATION" deals with the
contents of your .screenrc.
If your terminal is a "true" auto-margin terminal (it
doesn't allow the last position on the screen to be
updated without scrolling the screen) consider using a
version of your terminal's termcap that has automatic mar-
gins turned off. This will ensure an accurate and optimal
update of the screen in all circumstances. Most terminals
nowadays have "magic" margins (automatic margins plus
usable last column). This is the VT100 style type and per-
fectly suited for screen. If all you've got is a "true"
auto-margin terminal screen will be content to use it, but
updating a character put into the last position on the
screen may not be possible until the screen scrolls or the
character is moved into a safe position in some other way.
This delay can be shortened by using a terminal with
insert-character capability.
COMMAND-LINE OPTIONS
Screen has the following command-line options:
-a include all capabilities (with some minor exceptions)
in each window's termcap, even if screen must redraw
parts of the display in order to implement a func-
tion.
-A Adapt the sizes of all windows to the size of the
current terminal. By default, screen tries to
restore its old window sizes when attaching to resiz-
able terminals (those with "WS" in its description,
e.g. suncmd or some xterm).
-c file
override the default configuration file from
"$HOME/.screenrc" to file.
-d|-D [pid.tty.host]
does not start screen, but detaches the elsewhere
running screen session. It has the same effect as
typing "C-a d" from screen's controlling terminal. -D
is the equivalent to the power detach key. If no
session can be detached, this option is ignored. In
combination with the -r/-R option more powerful
effects can be achieved:
-d -r Reattach a session and if necessary detach it
first.
-d -R Reattach a session and if necessary detach or even
create it first.
-d -RR Reattach a session and if necessary detach or cre-
ate it. Use the first session if more than one
session is available.
-D -r Reattach a session. If necessary detach and logout
remotely first.
-D -R Attach here and now. In detail this means: If a
session is running, then reattach. If necessary
detach and logout remotely first. If it was not
running create it and notify the user. This is the
author's favorite.
-D -RR Attach here and now. Whatever that means, just do
it.
Note: It is always a good idea to check the status of
your sessions by means of "screen -list".
-e xy
specifies the command character to be x and the char-
acter generating a literal command character to y
(when typed after the command character). The
default is "C-a" and `a', which can be specified as
"-e^Aa". When creating a screen session, this option
sets the default command character. In a multiuser
session all users added will start off with this com-
mand character. But when attaching to an already run-
ning session, this option changes only the command
character of the attaching user. This option is
equivalent to either the commands "defescape" or
"escape" respectively.
-f, -fn, and -fa
turns flow-control on, off, or "automatic switching
mode". This can also be defined through the "def-
flow" .screenrc command.
-h num
Specifies the history scrollback buffer to be num
lines high.
-i will cause the interrupt key (usually C-c) to inter-
rupt the display immediately when flow-control is on.
See the "defflow" .screenrc command for details. The
use of this option is discouraged.
-l and -ln
turns login mode on or off (for /etc/utmp updating).
This can also be defined through the "deflogin"
.screenrc command.
-ls and -list
does not start screen, but prints a list of
pid.tty.host strings identifying your screen ses-
sions. Sessions marked `detached' can be resumed
with "screen -r". Those marked `attached' are running
and have a controlling terminal. If the session runs
in multiuser mode, it is marked `multi'. Sessions
marked as `unreachable' either live on a different
host or are `dead'. An unreachable session is con-
sidered dead, when its name matches either the name
of the local host, or the specified parameter, if
any. See the -r flag for a description how to con-
struct matches. Sessions marked as `dead' should be
thoroughly checked and removed. Ask your system
administrator if you are not sure. Remove sessions
with the -wipe option.
-L tells screen to turn on automatic output logging for
the windows.
-m causes screen to ignore the $STY environment vari-
able. With "screen -m" creation of a new session is
enforced, regardless whether screen is called from
within another screen session or not. This flag has a
special meaning in connection with the `-d' option:
-d -m Start screen in "detached" mode. This creates a
new session but doesn't attach to it. This is use-
ful for system startup scripts.
-D -m This also starts screen in "detached" mode, but
doesn't fork a new process. The command exits if
the session terminates.
-O selects a more optimal output mode for your terminal
rather than true VT100 emulation (only affects auto-
margin terminals without `LP'). This can also be set
in your .screenrc by specifying `OP' in a "termcap"
command.
-p number_or_name
Preselect a window. This is usefull when you want to
reattach to a specific windor or you want to send a
command via the "-X" option to a specific window. As
with screen's select commant, "-" selects the blank
window. As a special case for reattach, "=" brings up
the windowlist on the blank window.
-q Suppress printing of error messages. In combination
with "-ls" the exit value is as follows: 9 indicates
a directory without sessions. 10 indicates a direc-
tory with running but not attachable sessions. 11 (or
more) indicates 1 (or more) usable sessions. In com-
bination with "-r" the exit value is as follows: 10
indicates that there is no session to resume. 12 (or
more) indicates that there are 2 (or more) sessions
to resume and you should specify which one to choose.
In all other cases "-q" has no effect.
-r [pid.tty.host]
-r sessionowner/[pid.tty.host]
resumes a detached screen session. No other options
(except combinations with -d/-D) may be specified,
though an optional prefix of [pid.]tty.host may be
needed to distinguish between multiple detached
screen sessions. The second form is used to connect
to another user's screen session which runs in mul-
tiuser mode. This indicates that screen should look
for sessions in another user's directory. This
requires setuid-root.
-R attempts to resume the first detached screen session
it finds. If successful, all other command-line
options are ignored. If no detached session exists,
starts a new session using the specified options,
just as if -R had not been specified. The option is
set by default if screen is run as a login-shell
(actually screen uses "-xRR" in that case). For com-
binations with the -d/-D option see there.
-s sets the default shell to the program specified,
instead of the value in the environment variable
$SHELL (or "/bin/sh" if not defined). This can also
be defined through the "shell" .screenrc command.
-S sessionname
When creating a new session, this option can be used
to specify a meaningful name for the session. This
name identifies the session for "screen -list" and
"screen -r" actions. It substitutes the default
[tty.host] suffix.
-t name
sets the title (a.k.a.) for the default shell or
specified program. See also the "shelltitle"
.screenrc command.
-U Run screen in UTF-8 mode. This option tells screen
that your terminal sends and understands UTF-8
encoded characters. It also sets the default encoding
for new windows to `utf8'.
-v Print version number.
-wipe [match]
does the same as "screen -ls", but removes destroyed
sessions instead of marking them as `dead'. An
unreachable session is considered dead, when its name
matches either the name of the local host, or the
explicitly given parameter, if any. See the -r flag
for a description how to construct matches.
-x Attach to a not detached screen session. (Multi dis-
play mode).
-X Send the specified command to a running screen ses-
sion. You can use the -d or -r option to tell screen
to look only for attached or detached screen ses-
sions. Note that this command doesn't work if the
session is password protected.
DEFAULT KEY BINDINGS
As mentioned, each screen command consists of a "C-a" fol-
lowed by one other character. For your convenience, all
commands that are bound to lower-case letters are also
bound to their control character counterparts (with the
exception of "C-a a"; see below), thus, "C-a c" as well as
"C-a C-c" can be used to create a window. See section
"CUSTOMIZATION" for a description of the command.
The following table shows the default key bindings:
C-a ' (select) Prompt for a window name or num-
ber to switch to.
C-a " (windowlist -b)
Present a list of all windows
for selection.
C-a 0 (select 0)
... ...
C-a 9 (select 9)
C-a - (select -) Switch to window number 0 - 9,
or to the blank window.
C-a tab (focus) Switch the input focus to the
next region.
C-a C-a (other) Toggle to the window displayed
previously. Note that this
binding defaults to the command
character typed twice, unless
overridden. For instance, if
you use the option "-e]x", this
command becomes "]]".
C-a a (meta) Send the command character (C-a)
to window. See escape command.
C-a A (title) Allow the user to enter a name
for the current window.
C-a b
C-a C-b (break) Send a break to window.
C-a B (pow_break) Reopen the terminal line and
send a break.
C-a c
C-a C-c (screen) Create a new window with a shell
and switch to that window.
C-a C (clear) Clear the screen.
C-a d
C-a C-d (detach) Detach screen from this termi-
nal.
C-a D D (pow_detach) Detach and logout.
C-a f
C-a C-f (flow) Toggle flow on, off or auto.
C-a F (fit) Resize the window to the current
region size.
C-a C-g (vbell) Toggles screen's visual bell
mode.
C-a h (hardcopy) Write a hardcopy of the current
window to the file "hardcopy.n".
C-a H (log) Begins/ends logging of the cur-
rent window to the file "screen-
log.n".
C-a i
C-a C-i (info) Show info about this window.
C-a k
C-a C-k (kill) Destroy current window.
C-a l
C-a C-l (redisplay) Fully refresh current window.
C-a L (login) Toggle this windows login slot.
Available only if screen is con-
figured to update the utmp
database.
C-a m
C-a C-m (lastmsg) Repeat the last message dis-
played in the message line.
C-a M (monitor) Toggles monitoring of the cur-
rent window.
C-a space
C-a n
C-a C-n (next) Switch to the next window.
C-a N (number) Show the number (and title) of
the current window.
C-a backspace
C-a h
C-a p
C-a C-p (prev) Switch to the previous window
(opposite of C-a n).
C-a q
C-a C-q (xon) Send a control-q to the current
window.
C-a Q (only) Delete all regions but the cur-
rent one.
C-a r
C-a C-r (wrap) Toggle the current window's
line-wrap setting (turn the cur-
rent window's automatic margins
on and off).
C-a s
C-a C-s (xoff) Send a control-s to the current
window.
C-a S (split) Split the current region into
two new ones.
C-a t
C-a C-t (time) Show system information.
C-a v (version) Display the version and compila-
tion date.
C-a C-v (digraph) Enter digraph.
C-a w
C-a C-w (windows) Show a list of window.
C-a W (width) Toggle 80/132 columns.
C-a x
C-a C-x (lockscreen) Lock this terminal.
C-a X (remove) Kill the current region.
C-a z
C-a C-z (suspend) Suspend screen. Your system
must support BSD-style job-con-
trol.
C-a Z (reset) Reset the virtual terminal to
its "power-on" values.
C-a . (dumptermcap) Write out a ".termcap" file.
C-a ? (help) Show key bindings.
C-a C-\ (quit) Kill all windows and terminate
screen.
C-a : (colon) Enter command line mode.
C-a [
C-a C-[
C-a esc (copy) Enter copy/scrollback mode.
C-a ] (paste .) Write the contents of the paste
buffer to the stdin queue of the
current window.
C-a {
C-a } (history) Copy and paste a previous (com-
mand) line.
C-a > (writebuf) Write paste buffer to a file.
C-a < (readbuf) Reads the screen-exchange file
into the paste buffer.
C-a = (removebuf) Removes the file used by C-a <
and C-a >.
C-a , (license) Shows where screen comes from,
where it went to and why you can
use it.
C-a _ (silence) Start/stop monitoring the cur-
rent window for inactivity.
C-a * (displays) Show a listing of all currently
attached displays.
CUSTOMIZATION
The "socket directory" defaults either to $HOME/.screen or
simply to /tmp/screens or preferably to /usr/local/screens
chosen at compile-time. If screen is installed setuid-
root, then the administrator should compile screen with an
adequate (not NFS mounted) socket directory. If screen is
not running setuid-root, the user can specify any mode 700
directory in the environment variable $SCREENDIR.
When screen is invoked, it executes initialization com-
mands from the files "/usr/local/etc/screenrc" and
".screenrc" in the user's home directory. These are the
"programmer's defaults" that can be overridden in the fol-
lowing ways: for the global screenrc file screen searches
for the environment variable $SYSSCREENRC (this override
feature may be disabled at compile-time). The user spe-
cific screenrc file is searched in $SCREENRC, then
$HOME/.screenrc. The command line option -c takes prece-
dence over the above user screenrc files.
Commands in these files are used to set options, bind
functions to keys, and to automatically establish one or
more windows at the beginning of your screen session.
Commands are listed one per line, with empty lines being
ignored. A command's arguments are separated by tabs or
spaces, and may be surrounded by single or double quotes.
A `#' turns the rest of the line into a comment, except in
quotes. Unintelligible lines are warned about and
ignored. Commands may contain references to environment
variables. The syntax is the shell-like "$VAR " or
"${VAR}". Note that this causes incompatibility with pre-
vious screen versions, as now the '$'-character has to be
protected with '\' if no variable substitution shall be
performed. A string in single-quotes is also protected
from variable substitution.
Two configuration files are shipped as examples with your
screen distribution: "etc/screenrc" and "etc/etcscreenrc".
They contain a number of useful examples for various com-
mands.
Customization can also be done 'on-line'. To enter the
command mode type `C-a :'. Note that commands starting
with "def" change default values, while others change cur-
rent settings.
The following commands are available:
acladd usernames [crypted-pw]
addacl usernames
Enable users to fully access this screen session. User-
names can be one user or a comma separated list of users.
This command enables to attach to the screen session and
performs the equivalent of `aclchg usernames +rwx "#?"'.
executed. To add a user with restricted access, use the
`aclchg' command below. If an optional second parameter
is supplied, it should be a crypted password for the named
user(s). `Addacl' is a synonym to `acladd'. Multi user
mode only.
aclchg usernames permbits list
chacl usernames permbits list
Change permissions for a comma separated list of users.
Permission bits are represented as `r', `w' and `x'. Pre-
fixing `+' grants the permission, `-' removes it. The
third parameter is a comma separated list of commands
and/or windows (specified either by number or title). The
special list `#' refers to all windows, `?' to all com-
mands. if usernames consists of a single `*', all known
users are affected. A command can be executed when the
user has the `x' bit for it. The user can type input to a
window when he has its `w' bit set and no other user
obtains a writelock for this window. Other bits are cur-
rently ignored. To withdraw the writelock from another
user in window 2: `aclchg username -w+w 2'. To allow
read-only access to the session: `aclchg username -w "#"'.
As soon as a user's name is known to screen he can attach
to the session and (per default) has full permissions for
all command and windows. Execution permission for the acl
commands, `at' and others should also be removed or the
user may be able to regain write permission. Rights of
the special username nobody cannot be changed (see the
"su" command). `Chacl' is a synonym to `aclchg'. Multi
user mode only.
acldel username
Remove a user from screen's access control list. If cur-
rently attached, all the user's displays are detached from
the session. He cannot attach again. Multi user mode
only.
aclgrp username [groupname]
Creates groups of users that share common access rights.
The name of the group is the username of the group leader.
Each member of the group inherits the permissions that are
granted to the group leader. That means, if a user fails
an access check, another check is made for the group
leader. A user is removed from all groups the special
value "none" is used for groupname. If the second parame-
ter is omitted all groups the user is in are listed.
aclumask [[users]+bits |[users]-bits .... ]
umask [[users]+bits |[users]-bits .... ]
This specifies the access other users have to windows that
will be created by the caller of the command. Users may
be no, one or a comma separated list of known usernames.
If no users are specified, a list of all currently known
users is assumed. Bits is any combination of access con-
trol bits allowed defined with the "aclchg" command. The
special username "?" predefines the access that not yet
known users will be granted to any window initially. The
special username "??" predefines the access that not yet
known users are granted to any command. Rights of the
special username nobody cannot be changed (see the "su"
command). `Umask' is a synonym to `aclumask'.
activity message
When any activity occurs in a background window that is
being monitored, screen displays a notification in the
message line. The notification message can be re-defined
by means of the "activity" command. Each occurrence of
`%' in message is replaced by the number of the window in
which activity has occurred, and each occurrence of `^G'
is replaced by the definition for bell in your termcap
(usually an audible bell). The default message is
'Activity in window %n'
Note that monitoring is off for all windows by default,
but can be altered by use of the "monitor" command (C-a
M).
allpartial on|off
If set to on, only the current cursor line is refreshed on
window change. This affects all windows and is useful for
slow terminal lines. The previous setting of full/partial
refresh for each window is restored with "allpartial off".
This is a global flag that immediately takes effect on all
windows overriding the "partial" settings. It does not
change the default redraw behavior of newly created win-
dows.
altscreen on|off
If set to on, "alternate screen" support is enabled in
virtual terminals, just like in xterm. Initial setting is
`off'.
at [identifier][#|*|%] command [args ... ]
Execute a command at other displays or windows as if it
had been entered there. "At" changes the context (the
`current window' or `current display' setting) of the com-
mand. If the first parameter describes a non-unique con-
text, the command will be executed multiple times. If the
first parameter is of the form `identifier*' then identi-
fier is matched against user names. The command is exe-
cuted once for each display of the selected user(s). If
the first parameter is of the form `identifier%' identi-
fier is matched against displays. Displays are named after
the ttys they attach. The prefix `/dev/' or `/dev/tty' may
be omitted from the identifier. If identifier has a `#'
or nothing appended it is matched against window numbers
and titles. Omitting an identifier in front of the `#',
`*' or `%'-character selects all users, displays or win-
dows because a prefix-match is performed. Note that on the
affected display(s) a short message will describe what
happened. Permission is checked for initiator of the "at"
command, not for the owners of the affected display(s).
Note that the '#' character works as a comment introducer
when it is preceded by whitespace. This can be escaped by
prefixing a '\'. Permission is checked for the initiator
of the "at" command, not for the owners of the affected
display(s).
Caveat: When matching against windows, the command is exe-
cuted at least once per window. Commands that change the
internal arrangement of windows (like "other") may be
called again. In shared windows the command will be
repeated for each attached display. Beware, when issuing
toggle commands like "login"! Some commands (e.g. "pro-
cess") require that a display is associated with the tar-
get windows. These commands may not work correctly under
"at" looping over windows.
attrcolor attrib [attribute/color-modifier]
This command can be used to highlight attributes by chang-
ing the color of the text. If the attribute attrib is in
use, the specified attribute/color modifier is also
applied. If no modifier is given, the current one is
deleted. See the "STRING ESCAPES" chapter for the syntax
of the modifier. Screen understands two pseudo-attributes,
"i" stands for high-intensity foreground color and "I" for
high-intensity background color.
Examples:
attrcolor b "R"
Change the color to bright red if bold text is to be
printed.
attrcolor u "-u b"
Use blue text instead of underline.
attrcolor b ".I"
Use bright colors for bold text. Most terminal emulators
do this already.
attrcolor i "+b"
Make bright colored text also bold.
autodetach on|off
Sets whether screen will automatically detach upon hangup,
which saves all your running programs until they are
resumed with a screen-r command. When turned off, a
hangup signal will terminate screen and all the processes
it contains. Autodetach is on by default.
autonuke on|off
Sets whether a clear screen sequence should nuke all the
output that has not been written to the terminal. See also
"obuflimit".
backtick id lifespan autorefresh cmd args...
backtick id
Program the backtick command with the numerical id id.
The output of such a command is used for substitution of
the "%`" string escape. The specified lifespan is the num-
ber of seconds the output is considered valid. After this
time, the command is run again if a corresponding string
escape is encountered. The autorefresh parameter triggers
an automatic refresh for caption and hardstatus strings
after the specified number of seconds. Only the last line
of output is used for substitution.
If both the lifespan and the autorefresh parameters are
zero, the backtick program is expected to stay in the
background and generate output once in a while. In this
case, the command is executed right away and screen stores
the last line of output. If a new line gets printed screen
will automatically refresh the hardstatus or the captions.
The second form of the command deletes the backtick com-
mand with the numerical id id.
bce [on|off]
Change background-color-erase setting. If "bce" is set to
on, all characters cleared by an erase/insert/scroll/clear
operation will be displayed in the current background
color. Otherwise the default background color is used.
bell_msg [message]
When a bell character is sent to a background window,
screen displays a notification in the message line. The
notification message can be re-defined by this command.
Each occurrence of `%' in message is replaced by the num-
ber of the window to which a bell has been sent, and each
occurrence of `^G' is replaced by the definition for bell
in your termcap (usually an audible bell). The default
message is
'Bell in window %n'
An empty message can be supplied to the "bell_msg" command
to suppress output of a message line (bell_msg ""). With-
out parameter, the current message is shown.
bind [-c class] key [command [args]]
Bind a command to a key. By default, most of the commands
provided by screen are bound to one or more keys as indi-
cated in the "DEFAULT KEY BINDINGS" section, e.g. the com-
mand to create a new window is bound to "C-c" and "c".
The "bind" command can be used to redefine the key bind-
ings and to define new bindings. The key argument is
either a single character, a two-character sequence of the
form "^x" (meaning "C-x"), a backslash followed by an
octal number (specifying the ASCII code of the character),
or a backslash followed by a second character, such as
"\^" or "\\". The argument can also be quoted, if you
like. If no further argument is given, any previously
established binding for this key is removed. The command
argument can be any command listed in this section.
If a command class is specified via the "-c" option, the
key is bound for the specified class. Use the "command"
command to activate a class. Command classes can be used
to create multiple command keys or multi-character bind-
ings.
Some examples:
bind ' ' windows
bind ^k
bind k
bind K kill
bind ^f screen telnet foobar
bind \033 screen-ln -t root -h 1000 9 su
would bind the space key to the command that displays a
list of windows (so that the command usually invoked by
"C-a C-w" would also be available as "C-a space"). The
next three lines remove the default kill binding from "C-a
C-k" and "C-a k". "C-a K" is then bound to the kill com-
mand. Then it binds "C-f" to the command "create a window
with a TELNET connection to foobar", and bind "escape" to
the command that creates an non-login window with a.k.a.
"root" in slot #9, with a superuser shell and a scrollback
buffer of 1000 lines.
bind -c demo1 0 select 10
bind -c demo1 1 select 11
bind -c demo1 2 select 12
bindkey "^B" command -c demo1
makes "C-b 0" select window 10, "C-b 1" window 11, etc.
bind -c demo2 0 select 10
bind -c demo2 1 select 11
bind -c demo2 2 select 12
bind - command -c demo2
makes "C-a - 0" select window 10, "C-a - 1" window 11,
etc.
bindkey [-d] [-m] [-a] [[-k|-t] string [cmd args]]
This command manages screen's input translation tables.
Every entry in one of the tables tells screen how to react
if a certain sequence of characters is encountered. There
are three tables: one that should contain actions pro-
grammed by the user, one for the default actions used for
terminal emulation and one for screen's copy mode to do
cursor movement. See section "INPUT TRANSLATION" for a
list of default key bindings.
If the -d option is given, bindkey modifies the default
table, -m changes the copy mode table and with neither
option the user table is selected. The argument string is
the sequence of characters to which an action is bound.
This can either be a fixed string or a termcap keyboard
capability name (selectable with the -k option).
Some keys on a VT100 terminal can send a different string
if application mode is turned on (e.g the cursor keys).
Such keys have two entries in the translation table. You
can select the application mode entry by specifying the -a
option.
The -t option tells screen not to do inter-character tim-
ing. One cannot turn off the timing if a termcap capabil-
ity is used.
Cmd can be any of screen's commands with an arbitrary num-
ber of args. If cmd is omitted the key-binding is removed
from the table.
Here are some examples of keyboard bindings:
bindkey -d
Show all of the default key bindings. The application mode
entries are marked with [A].
bindkey -k k1 select 1
Make the "F1" key switch to window one.
bindkey -t foo stuff barfoo
Make "foo" an abbreviation of the word "barfoo". Timeout
is disabled so that users can type slowly.
bindkey "\024" mapdefault
This key-binding makes "^T" an escape character for key-
bindings. If you did the above "stuff barfoo" binding, you
can enter the word "foo" by typing "^Tfoo". If you want to
insert a "^T" you have to press the key twice (i.e. escape
the escape binding).
bindkey -k F1 command
Make the F11 (not F1!) key an alternative screen escape
(besides ^A).
break [duration]
Send a break signal for duration*0.25 seconds to this win-
dow. For non-Posix systems the time interval may be
rounded up to full seconds. Most useful if a character
device is attached to the window rather than a shell pro-
cess (See also chapter "WINDOW TYPES"). The maximum dura-
tion of a break signal is limited to 15 seconds.
breaktype [tcsendbreak|TIOCSBRK |TCSBRK]
Choose one of the available methods of generating a break
signal for terminal devices. This command should affect
the current window only. But it still behaves identical
to "defbreaktype". This will be changed in the future.
Calling "breaktype" with no parameter displays the break
method for the current window.
bufferfile [exchange-file]
Change the filename used for reading and writing with the
paste buffer. If the optional argument to the "buffer-
file" command is omitted, the default setting
("/tmp/screen-exchange") is reactivated. The following
example will paste the system's password file into the
screen window (using the paste buffer, where a copy
remains):
C-a : bufferfile /etc/passwd
C-a < C-a ]
C-a : bufferfile
c1 [on|off]
Change c1 code processing. "C1 on" tells screen to treat
the input characters between 128 and 159 as control func-
tions. Such an 8-bit code is normally the same as ESC
followed by the corresponding 7-bit code. The default set-
ting is to process c1 codes and can be changed with the
"defc1" command. Users with fonts that have usable char-
acters in the c1 positions may want to turn this off.
caption always|splitonly [string]
caption string [string]
This command controls the display of the window captions.
Normally a caption is only used if more than one window is
shown on the display (split screen mode). But if the type
is set to always screen shows a caption even if only one
window is displayed. The default is splitonly.
The second form changes the text used for the caption. You
can use all escapes from the "STRING ESCAPES" chapter.
Screen uses a default of `%3n %t'.
You can mix both forms by providing a string as an addi-
tional argument.
charset set
Change the current character set slot designation and
charset mapping. The first four character of set are
treated as charset designators while the fifth and sixth
character must be in range '0' to '3' and set the GL/GR
charset mapping. On every position a '.' may be used to
indicate that the corresponding charset/mapping should not
be changed (set is padded to six characters internally by
appending '.' chars). New windows have "BBBB02" as
default charset, unless a "encoding" command is active.
The current setting can be viewed with the "info" command.
chdir [directory]
Change the current directory of screen to the specified
directory or, if called without an argument, to your home
directory (the value of the environment variable $HOME).
All windows that are created by means of the "screen" com-
mand from within ".screenrc" or by means of "C-a : screen
..." or "C-a c" use this as their default directory.
Without a chdir command, this would be the directory from
which screen was invoked. Hardcopy and log files are
always written to the window's default directory, not the
current directory of the process running in the window.
You can use this command multiple times in your .screenrc
to start various windows in different default directories,
but the last chdir value will affect all the windows you
create interactively.
clear
Clears the current window and saves its image to the
scrollback buffer.
colon [prefix]
Allows you to enter ".screenrc" command lines. Useful for
on-the-fly modification of key bindings, specific window
creation and changing settings. Note that the "set" key-
word no longer exists! Usually commands affect the current
window rather than default settings for future windows.
Change defaults with commands starting with 'def...'.
If you consider this as the `Ex command mode' of screen,
you may regard "C-a esc" (copy mode) as its `Vi command
mode'.
command [-c class]
This command has the same effect as typing the screen
escape character (^A). It is probably only useful for key
bindings. If the "-c" option is given, select the speci-
fied command class. See also "bind" and "bindkey".
compacthist [on|off]
This tells screen whether to suppress trailing blank lines
when scrolling up text into the history buffer.
console [on|off]
Grabs or un-grabs the machines console output to a window.
Note: Only the owner of /dev/console can grab the console
output. This command is only available if the machine
supports the ioctl TIOCCONS.
copy
Enter copy/scrollback mode. This allows you to copy text
from the current window and its history into the paste
buffer. In this mode a vi-like `full screen editor' is
active:
Movement keys:
h, j, k, l move the cursor line by line or column by
column.
0, ^ and $ move to the leftmost column, to the first or
last non-whitespace character on the line.
H, M and L move the cursor to the leftmost column of the
top, center or bottom line of the window.
+ and - positions one line up and down.
G moves to the specified absolute line (default: end of
buffer).
| moves to the specified absolute column.
w, b, e move the cursor word by word.
B, E move the cursor WORD by WORD (as in vi).
C-u and C-d scroll the display up/down by the specified
amount of lines while preserving the cursor position.
(Default: half screen-full).
C-b and C-f scroll the display up/down a full screen.
g moves to the beginning of the buffer.
% jumps to the specified percentage of the buffer.
Note:
Emacs style movement keys can be customized by a
.screenrc command. (E.g. markkeys "h=^B:l=^F:$=^E")
There is no simple method for a full emacs-style
keymap, as this involves multi-character codes.
Marking:
The copy range is specified by setting two marks. The
text between these marks will be highlighted. Press
space to set the first or second mark respectively.
Y and y used to mark one whole line or to mark from
start of line.
W marks exactly one word.
Repeat count:
Any of these commands can be prefixed with a repeat
count number by pressing digits
0..9 which is taken as a repeat count.
Example: "C-a C-[ H 10 j 5 Y" will copy lines 11 to 15
into the paste buffer.
Searching:
/ Vi-like search forward.
? Vi-like search backward.
C-a s Emacs style incremental search forward.
C-r Emacs style reverse i-search.
Specials:
There are however some keys that act differently than
in vi. Vi does not allow one to yank rectangular
blocks of text, but screen does. Press
c or C to set the left or right margin respectively. If
no repeat count is given, both default to the current
cursor position.
Example: Try this on a rather full text screen: "C-a [
M 20 l SPACE c 10 l 5 j C SPACE".
This moves one to the middle line of the screen, moves
in 20 columns left, marks the beginning of the paste
buffer, sets the left column, moves 5 columns down,
sets the right column, and then marks the end of the
paste buffer. Now try:
"C-a [ M 20 l SPACE 10 l 5 j SPACE"
and notice the difference in the amount of text
copied.
J joins lines. It toggles between 4 modes: lines sepa-
rated by a newline character (012), lines glued seam-
less, lines separated by a single whitespace and comma
separated lines. Note that you can prepend the newline
character with a carriage return character, by issuing
a "crlf on".
v is for all the vi users with ":set numbers" - it tog-
gles the left margin between column 9 and 1. Press
a before the final space key to toggle in append mode.
Thus the contents of the paste buffer will not be
overwritten, but is appended to.
A toggles in append mode and sets a (second) mark.
> sets the (second) mark and writes the contents of the
paste buffer to the screen-exchange file (/tmp/screen-
exchange per default) once copy-mode is finished.
This example demonstrates how to dump the whole
scrollback buffer to that file: "C-A [ g SPACE G $ >".
C-g gives information about the current line and column.
x exchanges the first mark and the current cursor posi-
tion. You can use this to adjust an already placed
mark.
@ does nothing. Does not even exit copy mode.
All keys not described here exit copy mode.
copy_reg [key]
No longer exists, use "readreg" instead.
crlf [on|off]
This affects the copying of text regions with the `C-a ['
command. If it is set to `on', lines will be separated by
the two character sequence `CR' - `LF'. Otherwise
(default) only `LF' is used. When no parameter is given,
the state is toggled.
debug on|off
Turns runtime debugging on or off. If screen has been com-
piled with option -DDEBUG debugging available and is
turned on per default. Note that this command only affects
debugging output from the main "SCREEN" process correctly.
Debug output from attacher processes can only be turned
off once and forever.
defc1 on|off
Same as the c1 command except that the default setting for
new windows is changed. Initial setting is `on'.
defautonuke on|off
Same as the autonuke command except that the default set-
ting for new displays is changed. Initial setting is
`off'. Note that you can use the special `AN' terminal
capability if you want to have a dependency on the termi-
nal type.
defbce on|off
Same as the bce command except that the default setting
for new windows is changed. Initial setting is `off'.
defbreaktype [tcsendbreak|TIOCSBRK |TCSBRK]
Choose one of the available methods of generating a break
signal for terminal devices. The preferred methods are
tcsendbreak and TIOCSBRK. The third, TCSBRK, blocks the
complete screen session for the duration of the break, but
it may be the only way to generate long breaks. Tcsend-
break and TIOCSBRK may or may not produce long breaks with
spikes (e.g. 4 per second). This is not only system depen-
dant, this also differs between serial board drivers.
Calling "defbreaktype" with no parameter displays the cur-
rent setting.
defcharset [set]
Like the charset command except that the default setting
for new windows is changed. Shows current default if
called without argument.
defescape xy
Set the default command characters. This is equivalent to
the "escape" except that it is useful multiuser sessions
only. In a multiuser session "escape" changes the command
character of the calling user, where "defescape" changes
the default command characters for users that will be
added later.
defflow on|off|auto [interrupt]
Same as the flow command except that the default setting
for new windows is changed. Initial setting is `auto'.
Specifying "defflow auto interrupt" is the same as the
command-line options -fa and -i.
defgr on|off
Same as the gr command except that the default setting for
new windows is changed. Initial setting is `off'.
defhstatus [status]
The hardstatus line that all new windows will get is set
to status. This command is useful to make the hardstatus
of every window display the window number or title or the
like. Status may contain the same directives as in the
window messages, but the directive escape character is
'^E' (octal 005) instead of '%'. This was done to make a
misinterpretation of program generated hardstatus lines
impossible. If the parameter status is omitted, the cur-
rent default string is displayed. Per default the hard-
status line of new windows is empty.
defencoding enc
Same as the encoding command except that the default set-
ting for new windows is changed. Initial setting is the
encoding taken from the terminal.
deflog on|off
Same as the log command except that the default setting
for new windows is changed. Initial setting is `off'.
deflogin on|off
Same as the login command except that the default setting
for new windows is changed. This is initialized with `on'
as distributed (see config.h.in).
defmode mode
The mode of each newly allocated pseudo-tty is set to
mode. Mode is an octal number. When no "defmode" command
is given, mode 0622 is used.
defmonitor on|off
Same as the monitor command except that the default set-
ting for new windows is changed. Initial setting is `off'.
defobuflimit limit
Same as the obuflimit command except that the default set-
ting for new displays is changed. Initial setting is 256
bytes. Note that you can use the special 'OL' terminal
capability if you want to have a dependency on the termi-
nal type.
defscrollback num
Same as the scrollback command except that the default
setting for new windows is changed. Initial setting is
100.
defshell command
Synonym to the shell command. See there.
defsilence on|off
Same as the silence command except that the default set-
ting for new windows is changed. Initial setting is `off'.
defslowpaste msec"
Same as the slowpaste command except that the default set-
ting for new windows is changed. Initial setting is 0 mil-
liseconds, meaning `off'.
defutf8 on|off
Same as the utf8 command except that the default setting
for new windows is changed. Initial setting is `on' if
screen was started with "-U", otherwise `off'.
defwrap on|off
Same as the wrap command except that the default setting
for new windows is changed. Initially line-wrap is on and
can be toggled with the "wrap" command ("C-a r") or by
means of "C-a : wrap on|off".
defwritelock on|off|auto
Same as the writelock command except that the default set-
ting for new windows is changed. Initially writelocks will
off.
defzombie [keys]
Synonym to the zombie command. Both currently change the
default. See there.
detach [-h]
Detach the screen session (disconnect it from the terminal
and put it into the background). This returns you to the
shell where you invoked screen. A detached screen can be
resumed by invoking screen with the -r option (see also
section "COMMAND-LINE OPTIONS"). The -h option tells
screen to immediately close the connection to the terminal
("hangup").
dinfo
Show what screen thinks about your terminal. Useful if you
want to know why features like color or the alternate
charset don't work.
displays
Shows a tabular listing of all currently connected user
front-ends (displays). This is most useful for multiuser
sessions.
digraph [preset]
This command prompts the user for a digraph sequence. The
next two characters typed are looked up in a builtin table
and the resulting character is inserted in the input
stream. For example, if the user enters 'a"', an a-umlaut
will be inserted. If the first character entered is a 0
(zero), screen will treat the following characters (up to
three) as an octal number instead. The optional argument
preset is treated as user input, thus one can create an
"umlaut" key. For example the command "bindkey ^K digraph
'"'" enables the user to generate an a-umlaut by typing
CTRL-K a.
dumptermcap
Write the termcap entry for the virtual terminal optimized
for the currently active window to the file ".termcap" in
the user's "$HOME/.screen" directory (or wherever screen
stores its sockets. See the "FILES" section below). This
termcap entry is identical to the value of the environment
variable $TERMCAP that is set up by screen for each win-
dow. For terminfo based systems you will need to run a
converter like captoinfo and then compile the entry with
tic.
echo [-n] message
The echo command may be used to annoy screen users with a
'message of the day'. Typically installed in a global
/local/etc/screenrc. The option "-n" may be used to sup-
press the line feed. See also "sleep". Echo is also use-
ful for online checking of environment variables.
escape xy
Set the command character to x and the character generat-
ing a literal command character (by triggering the "meta"
command) to y (similar to the -e option). Each argument
is either a single character, a two-character sequence of
the form "^x" (meaning "C-x"), a backslash followed by an
octal number (specifying the ASCII code of the character),
or a backslash followed by a second character, such as
"\^" or "\\". The default is "^Aa".
eval command1 [command2 ...]
Parses and executes each argument as separate command.
exec [[fdpat] newcommand [args ...]]
Run a unix subprocess (specified by an executable path
newcommand and its optional arguments) in the current win-
dow. The flow of data between newcommands stdin/std-
out/stderr, the process originally started in the window
(let us call it "application-process") and screen itself
(window) is controlled by the filedescriptor pattern
fdpat. This pattern is basically a three character
sequence representing stdin, stdout and stderr of newcom-
mand. A dot (.) connects the file descriptor to screen.
An exclamation mark (!) causes the file descriptor to be
connected to the application-process. A colon (:) combines
both. User input will go to newcommand unless newcommand
receives the application-process' output (fdpats first
character is `!' or `:') or a pipe symbol (|) is added (as
a fourth character) to the end of fdpat.
Invoking `exec' without arguments shows name and arguments
of the currently running subprocess in this window. Only
one subprocess a time can be running in each window.
When a subprocess is running the `kill' command will
affect it instead of the windows process.
Refer to the postscript file `doc/fdpat.ps' for a confus-
ing illustration of all 21 possible combinations. Each
drawing shows the digits 2,1,0 representing the three file
descriptors of newcommand. The box marked `W' is the usual
pty that has the application-process on its slave side.
The box marked `P' is the secondary pty that now has
screen at its master side.
Abbreviations:
Whitespace between the word `exec' and fdpat and the com-
mand can be omitted. Trailing dots and a fdpat consisting
only of dots can be omitted. A simple `|' is synonymous
for the pattern `!..|'; the word exec can be omitted here
and can always be replaced by `!'.
Examples:
exec ... /bin/sh
exec /bin/sh
!/bin/sh
Creates another shell in the same window, while the origi-
nal shell is still running. Output of both shells is dis-
played and user input is sent to the new /bin/sh.
exec !.. stty 19200
exec ! stty 19200
!!stty 19200
Set the speed of the window's tty. If your stty command
operates on stdout, then add another `!'.
exec !..| less
|less
This adds a pager to the window output. The special char-
acter `|' is needed to give the user control over the
pager although it gets its input from the window's pro-
cess. This works, because less listens on stderr (a behav-
ior that screen would not expect without the `|') when its
stdin is not a tty. Less versions newer than 177 fail
miserably here; good old pg still works.
!:sed -n s/.*Error.*/\007/p
Sends window output to both, the user and the sed command.
The sed inserts an additional bell character (oct. 007) to
the window output seen by screen. This will cause "Bell
in window x" messages, whenever the string "Error" appears
in the window.
fit
Change the window size to the size of the current region.
This command is needed because screen doesn't adapt the
window size automatically if the window is displayed more
than once.
flow [on|off|auto]
Sets the flow-control mode for this window. Without
parameters it cycles the current window's flow-control
setting from "automatic" to "on" to "off". See the dis-
cussion on "FLOW-CONTROL" later on in this document for
full details and note, that this is subject to change in
future releases. Default is set by `defflow'.
focus [up|down|top|bottom]
Move the input focus to the next region. This is done in a
cyclic way so that the top region is selected after the
bottom one. If no subcommand is given it defaults to
`down'. `up' cycles in the opposite order, `top' and `bot-
tom' go to the top and bottom region respectively. Useful
bindings are (j and k as in vi)
bind j focus down
bind k focus up
bind t focus top
bind b focus bottom
gr [on|off]
Turn GR charset switching on/off. Whenever screen sees an
input character with the 8th bit set, it will use the
charset stored in the GR slot and print the character with
the 8th bit stripped. The default (see also "defgr") is
not to process GR switching because otherwise the ISO88591
charset would not work.
hardcopy [-h] [file]
Writes out the currently displayed image to the file file,
or, if no filename is specified, to hardcopy.n in the
default directory, where n is the number of the current
window. This either appends or overwrites the file if it
exists. See below. If the option -h is specified, dump
also the contents of the scrollback buffer.
hardcopy_append on|off
If set to "on", screen will append to the "hardcopy.n"
files created by the command "C-a h", otherwise these
files are overwritten each time. Default is `off'.
hardcopydir directory
Defines a directory where hardcopy files will be placed.
If unset, hardcopys are dumped in screen's current working
directory.
hardstatus [on|off]
hardstatus [always]lastline|message|ignore [string]
hardstatus string [string]
This command configures the use and emulation of the ter-
minal's hardstatus line. The first form toggles whether
screen will use the hardware status line to display mes-
sages. If the flag is set to `off', these messages are
overlaid in reverse video mode at the display line. The
default setting is `on'.
The second form tells screen what to do if the terminal
doesn't have a hardstatus line (i.e. the termcap/terminfo
capabilities "hs", "ts", "fs" and "ds" are not set). If
the type "lastline" is used, screen will reserve the last
line of the display for the hardstatus. "message" uses
screen's message mechanism and "ignore" tells screen never
to display the hardstatus. If you prepend the word
"always" to the type (e.g., "alwayslastline"), screen will
use the type even if the terminal supports a hardstatus.
The third form specifies the contents of the hardstatus
line. '%h' is used as default string, i.e. the stored
hardstatus of the current window (settable via
"ESC]0;<string>^G" or "ESC_<string>ESC\") is displayed.
You can customize this to any string you like including
the escapes from the "STRING ESCAPES" chapter. If you
leave out the argument string, the current string is dis-
played.
You can mix the second and third form by providing the
string as additional argument.
height [-w|-d] [lines [cols]]
Set the display height to a specified number of lines.
When no argument is given it toggles between 24 and 42
lines display. You can also specify a width if you want to
change both values. The -w option tells screen to leave
the display size unchanged and just set the window size,
-d vice versa.
help [-c class]
Not really a online help, but displays a help screen show-
ing you all the key bindings. The first pages list all
the internal commands followed by their current bindings.
Subsequent pages will display the custom commands, one
command per key. Press space when you're done reading
each page, or return to exit early. All other characters
are ignored. If the "-c" option is given, display all
bound commands for the specified command class. See also
"DEFAULT KEY BINDINGS" section.
history
Usually users work with a shell that allows easy access to
previous commands. For example csh has the command "!!"
to repeat the last command executed. Screen allows you to
have a primitive way of re-calling "the command that
started ...": You just type the first letter of that com-
mand, then hit `C-a {' and screen tries to find a previous
line that matches with the `prompt character' to the left
of the cursor. This line is pasted into this window's
input queue. Thus you have a crude command history (made
up by the visible window and its scrollback buffer).
hstatus status
Change the window's hardstatus line to the string status.
ignorecase [on|off]
Tell screen to ignore the case of characters in searches.
Default is `off'.
info
Uses the message line to display some information about
the current window: the cursor position in the form "(col-
umn,row)" starting with "(1,1)", the terminal width and
height plus the size of the scrollback buffer in lines,
like in "(80,24)+50", the current state of window XON/XOFF
flow control is shown like this (See also section FLOW
CONTROL):
+flow automatic flow control, currently on.
-flow automatic flow control, currently off.
+(+)flow flow control enabled. Agrees with automatic control.
-(+)flow flow control disabled. Disagrees with automatic control.
+(-)flow flow control enabled. Disagrees with automatic control.
-(-)flow flow control disabled. Agrees with automatic control.
The current line wrap setting (`+wrap' indicates enabled,
`-wrap' not) is also shown. The flags `ins', `org', `app',
`log', `mon' or `nored' are displayed when the window is
in insert mode, origin mode, application-keypad mode, has
output logging, activity monitoring or partial redraw
enabled.
The currently active character set (G0, G1, G2, or G3) and
in square brackets the terminal character sets that are
currently designated as G0 through G3 is shown. If the
window is in UTF-8 mode, the string "UTF-8" is shown
instead.
Additional modes depending on the type of the window are
displayed at the end of the status line (See also chapter
"WINDOW TYPES").
If the state machine of the terminal emulator is in a non-
default state, the info line is started with a string
identifying the current state.
For system information use the "time" command.
ins_reg [key]
No longer exists, use "paste" instead.
encoding enc [enc]
Tell screen how to interpret the input/output. The first
argument sets the encoding of the current window. Each
window can emulate a different encoding. The optional sec-
ond parameter overwrites the encoding of the connected
terminal. It should never be needed as screen uses the
locale setting to detect the encoding. There is also a
way to select a terminal encoding depending on the termi-
nal type by using the "KJ" termcap entry.
Supported encodings are eucJP, SJIS, eucKR, eucCN, Big5,
GBK, KOI8-R, CP1251, UTF-8, ISO8859-2, ISO8859-3,
ISO8859-4, ISO8859-5, ISO8859-6, ISO8859-7, ISO8859-8,
ISO8859-9, ISO8859-10, ISO8859-15, jis.
See also "defencoding", which changes the default setting
of a new window.
kill
Kill current window.
If there is an `exec' command running then it is killed.
Otherwise the process (shell) running in the window
receives a HANGUP condition, the window structure is
removed and screen (your display) switches to another win-
dow. When the last window is destroyed, screen exits.
After a kill screen switches to the previously displayed
window.
Note: Emacs users should keep this command in mind, when
killing a line. It is recommended not to use "C-a" as the
screen escape key or to rebind kill to "C-a K".
lastmsg
Redisplay the last contents of the message/status line.
Useful if you're typing when a message appears, because
the message goes away when you press a key (unless your
terminal has a hardware status line). Refer to the com-
mands "msgwait" and "msgminwait" for fine tuning.
license
Display the disclaimer page. This is done whenever screen
is started without options, which should be often enough.
See also the "startup_message" command.
lockscreen
Lock this display. Call a screenlock program
(/local/bin/lck or /usr/bin/lock or a builtin if no other
is available). Screen does not accept any command keys
until this program terminates. Meanwhile processes in the
windows may continue, as the windows are in the `detached'
state. The screenlock program may be changed through the
environment variable $LOCKPRG (which must be set in the
shell from which screen is started) and is executed with
the user's uid and gid.
Warning: When you leave other shells unlocked and you have
no password set on screen, the lock is void: One could
easily re-attach from an unlocked shell. This feature
should rather be called `lockterminal'.
log [on|off]
Start/stop writing output of the current window to a file
"screenlog.n" in the window's default directory, where n
is the number of the current window. This filename can be
changed with the `logfile' command. If no parameter is
given, the state of logging is toggled. The session log is
appended to the previous contents of the file if it
already exists. The current contents and the contents of
the scrollback history are not included in the session
log. Default is `off'.
logfile filename
logfile flush secs
Defines the name the logfiles will get. The default is
"screenlog.%n". The second form changes the number of sec-
onds screen will wait before flushing the logfile buffer
to the file-system. The default value is 10 seconds.
login [on|off]
Adds or removes the entry in the utmp database file for
the current window. This controls if the window is
`logged in'. When no parameter is given, the login state
of the window is toggled. Additionally to that toggle, it
is convenient having a `log in' and a `log out' key. E.g.
`bind I login on' and `bind O login off' will map these
keys to be C-a I and C-a O. The default setting (in con-
fig.h.in) should be "on" for a screen that runs under
suid-root. Use the "deflogin" command to change the
default login state for new windows. Both commands are
only present when screen has been compiled with utmp sup-
port.
logtstamp [on|off]
logtstamp after [secs]
logtstamp string [string]
This command controls logfile time-stamp mechanism of
screen. If time-stamps are turned "on", screen adds a
string containing the current time to the logfile after
two minutes of inactivity. When output continues and more
than another two minutes have passed, a second time-stamp
is added to document the restart of the output. You can
change this timeout with the second form of the command.
The third form is used for customizing the time-stamp
string (`-- %n:%t -- time-stamp -- %M/%d/%y %c:%s --\n' by
default).
mapdefault
Tell screen that the next input character should only be
looked up in the default bindkey table. See also "bind-
key".
mapnotnext
Like mapdefault, but don't even look in the default bind-
key table.
maptimeout [timo]
Set the inter-character timer for input sequence detection
to a timeout of timo ms. The default timeout is 300ms.
Maptimeout with no arguments shows the current setting.
See also "bindkey".
markkeys string
This is a method of changing the keymap used for copy/his-
tory mode. The string is made up of oldchar=newchar pairs
which are separated by `:'. Example: The string
"B=^B:F=^F" will change the keys `C-b' and `C-f' to the vi
style binding (scroll up/down fill page). This happens to
be the default binding for `B' and `F'. The command
"markkeys h=^B:l=^F:$=^E" would set the mode for an emacs-
style binding. If your terminal sends characters, that
cause you to abort copy mode, then this command may help
by binding these characters to do nothing. The no-op
character is `@' and is used like this: "markkeys @=L=H"
if you do not want to use the `H' or `L' commands any
longer. As shown in this example, multiple keys can be
assigned to one function in a single statement.
maxwin num
Set the maximum window number screen will create. Doesn't
affect already existing windows. The number may only be
decreased.
meta
Insert the command character (C-a) in the current window's
input stream.
monitor [on|off]
Toggles activity monitoring of windows. When monitoring
is turned on and an affected window is switched into the
background, you will receive the activity notification
message in the status line at the first sign of output and
the window will also be marked with an `@' in the window-
status display. Monitoring is initially off for all win-
dows.
msgminwait sec
Defines the time screen delays a new message when one mes-
sage is currently displayed. The default is 1 second.
msgwait sec
Defines the time a message is displayed if screen is not
disturbed by other activity. The default is 5 seconds.
multiuser on|off
Switch between singleuser and multiuser mode. Standard
screen operation is singleuser. In multiuser mode the com-
mands `acladd', `aclchg', `aclgrp' and `acldel' can be
used to enable (and disable) other users accessing this
screen session.
nethack on|off
Changes the kind of error messages used by screen. When
you are familiar with the game "nethack", you may enjoy
the nethack-style messages which will often blur the facts
a little, but are much funnier to read. Anyway, standard
messages often tend to be unclear as well.
This option is only available if screen was compiled with
the NETHACK flag defined. The default setting is then
determined by the presence of the environment variable
$NETHACKOPTIONS.
next
Switch to the next window. This command can be used
repeatedly to cycle through the list of windows.
nonblock [on|off]
Enable or disable flow control for the current user inter-
face (display). It is used to prevent a slow display from
slowing down the processing of data output by a window.
This command may be helpful when multiple displays show
the same window. Nonblock is initially off for all dis-
plays.
number [n]
Change the current windows number. If the given number n
is already used by another window, both windows exchange
their numbers. If no argument is specified, the current
window number (and title) is shown.
obuflimit [limit]
If the output buffer contains more bytes than the speci-
fied limit, no more data will be read from the windows.
The default value is 256. If you have a fast display (like
xterm), you can set it to some higher value. If no argu-
ment is specified, the current setting is displayed.
only
Kill all regions but the current one.
other
Switch to the window displayed previously. If this window
does no longer exist, other has the same effect as next.
partial on|off
Defines whether the display should be refreshed (as with
redisplay) after switching to the current window. This
command only affects the current window. To immediately
affect all windows use the allpartial command. Default is
`off', of course. This default is fixed, as there is cur-
rently no defpartial command.
password [crypted_pw]
Present a crypted password in your ".screenrc" file and
screen will ask for it, whenever someone attempts to
resume a detached. This is useful if you have privileged
programs running under screen and you want to protect your
session from reattach attempts by another user masquerad-
ing as your uid (i.e. any superuser.) If no crypted pass-
word is specified, screen prompts twice for typing a pass-
word and places its encryption in the paste buffer.
Default is `none', this disables password checking.
paste [registers [dest_reg]]
Write the (concatenated) contents of the specified regis-
ters to the stdin queue of the current window. The regis-
ter '.' is treated as the paste buffer. If no parameter is
given the user is prompted for a single register to paste.
The paste buffer can be filled with the copy, history and
readbuf commands. Other registers can be filled with the
register, readreg and paste commands. If paste is called
with a second argument, the contents of the specified reg-
isters is pasted into the named destination register
rather than the window. If '.' is used as the second argu-
ment, the displays paste buffer is the destination. Note,
that "paste" uses a wide variety of resources: Whenever a
second argument is specified no current window is needed.
When the source specification only contains registers (not
the paste buffer) then there need not be a current display
(terminal attached), as the registers are a global
resource. The paste buffer exists once for every user.
pastefont [on|off]
Tell screen to include font information in the paste
buffer. The default is not to do so. This command is espe-
cially useful for multi character fonts like kanji.
pow_break
Reopen the window's terminal line and send a break condi-
tion. See `break'.
pow_detach
Power detach. Mainly the same as detach, but also sends a
HANGUP signal to the parent process of screen. CAUTION:
This will result in a logout, when screen was started from
your login shell.
pow_detach_msg [message]
The message specified here is output whenever a `Power
detach' was performed. It may be used as a replacement for
a logout message or to reset baud rate, etc. Without
parameter, the current message is shown.
prev
Switch to the window with the next lower number. This
command can be used repeatedly to cycle through the list
of windows.
printcmd [cmd]
If cmd is not an empty string, screen will not use the
terminal capabilities "po/pf" if it detects an ansi print
sequence ESC [ 5 i, but pipe the output into cmd. This
should normally be a command like "lpr" or "'cat >
/tmp/scrprint'". printcmd without a command displays the
current setting. The ansi sequence ESC \ ends printing
and closes the pipe.
Warning: Be careful with this command! If other user have
write access to your terminal, they will be able to fire
off print commands.
process [key]
Stuff the contents of the specified register into screen's
input queue. If no argument is given you are prompted for
a register name. The text is parsed as if it had been
typed in from the user's keyboard. This command can be
used to bind multiple actions to a single key.
quit
Kill all windows and terminate screen. Note that on
VT100-style terminals the keys C-4 and C-\ are identical.
This makes the default bindings dangerous: Be careful not
to type C-a C-4 when selecting window no. 4. Use the
empty bind command (as in "bind '^\'") to remove a key
binding.
readbuf [-e encoding] [filename]
Reads the contents of the specified file into the paste
buffer. You can tell screen the encoding of the file via
the -e option. If no file is specified, the screen-
exchange filename is used. See also "bufferfile" command.
readreg [-e encoding] [register [filename]]
Does one of two things, dependent on number of arguments:
with zero or one arguments it it duplicates the paste
buffer contents into the register specified or entered at
the prompt. With two arguments it reads the contents of
the named file into the register, just as readbuf reads
the screen-exchange file into the paste buffer. You can
tell screen the encoding of the file via the -e option.
The following example will paste the system's password
file into the screen window (using register p, where a
copy remains):
C-a : readreg p /etc/passwd
C-a : paste p
redisplay
Redisplay the current window. Needed to get a full redis-
play when in partial redraw mode.
register [-e encoding] key string
Save the specified string to the register key. The encod-
ing of the string can be specified via the -e option. See
also the "paste" command.
remove
Kill the current region. This is a no-op if there is only
one region.
removebuf
Unlinks the screen-exchange file used by the commands
"writebuf" and "readbuf".
reset
Reset the virtual terminal to its "power-on" values. Use-
ful when strange settings (like scroll regions or graphics
character set) are left over from an application.
resize
Resize the current region. The space will be removed from
or added to the region below or if there's not enough
space from the region above.
resize +N increase current region height by N
resize -N decrease current region height by N
resize N set current region height to N
resize = make all windows equally high
resize max maximize current region height
resize min minimize current region height
screen [-opts] [n] [cmd [args]]
Establish a new window. The flow-control options (-f, -fn
and -fa), title (a.k.a.) option (-t), login options (-l
and -ln) , terminal type option (-T <term>), the all-capa-
bility-flag (-a) and scrollback option (-h <num>) may be
specified with each command. The option (-M) turns moni-
toring on for this window. The option (-L) turns output
logging on for this window. If an optional number n in
the range 0..9 is given, the window number n is assigned
to the newly created window (or, if this number is already
in-use, the next available number). If a command is spec-
ified after "screen", this command (with the given argu-
ments) is started in the window; otherwise, a shell is
created. Thus, if your ".screenrc" contains the lines
# example for .screenrc:
screen 1
screen-fn -t foobar -L 2 telnet foobar
screen creates a shell window (in window #1) and a window
with a TELNET connection to the machine foobar (with no
flow-control using the title "foobar" in window #2) and
will write a logfile ("screenlog.2") of the telnet ses-
sion. Note, that unlike previous versions of screen no
additional default window is created when "screen" com-
mands are included in your ".screenrc" file. When the ini-
tialization is completed, screen switches to the last win-
dow specified in your .screenrc file or, if none, opens a
default window #0.
Screen has built in some functionality of "cu" and "tel-
net". See also chapter "WINDOW TYPES".
scrollback num
Set the size of the scrollback buffer for the current win-
dows to num lines. The default scrollback is 100 lines.
See also the "defscrollback" command and use "C-a i" to
view the current setting.
select [WindowID]
Switch to the window identified by WindowID. This can be
a prefix of a window title (alphanumeric window name) or a
window number. The parameter is optional and if omitted,
you get prompted for an identifier. When a new window is
established, the first available number is assigned to
this window. Thus, the first window can be activated by
"select 0". The number of windows is limited at compile-
time by the MAXWIN configuration parameter.
sessionname [name]
Rename the current session. Note, that for "screen -list"
the name shows up with the process-id prepended. If the
argument "name" is omitted, the name of this session is
displayed. Caution: The $STY environment variables still
reflects the old name. This may result in confusion. The
default is constructed from the tty and host names.
setenv [var [string]]
Set the environment variable var to value string. If only
var is specified, the user will be prompted to enter a
value. If no parameters are specified, the user will be
prompted for both variable and value. The environment is
inherited by all subsequently forked shells.
setsid [on|off]
Normally screen uses different sessions and process groups
for the windows. If setsid is turned off, this is not done
anymore and all windows will be in the same process group
as the screen backend process. This also breaks job-con-
trol, so be careful. The default is on, of course. This
command is probably useful only in rare circumstances.
shell command
Set the command to be used to create a new shell. This
overrides the value of the environment variable $SHELL.
This is useful if you'd like to run a tty-enhancer which
is expecting to execute the program specified in $SHELL.
If the command begins with a '-' character, the shell will
be started as a login-shell.
shelltitle title
Set the title for all shells created during startup or by
the C-A C-c command. For details about what a title is,
see the discussion entitled "TITLES (naming windows)".
silence [on|off|sec]
Toggles silence monitoring of windows. When silence is
turned on and an affected window is switched into the
background, you will receive the silence notification mes-
sage in the status line after a specified period of inac-
tivity (silence). The default timeout can be changed with
the `silencewait' command or by specifying a number of
seconds instead of `on' or `off'. Silence is initially
off for all windows.
silencewait sec
Define the time that all windows monitored for silence
should wait before displaying a message. Default 30 sec-
onds.
sleep num
This command will pause the execution of a .screenrc file
for num seconds. Keyboard activity will end the sleep.
It may be used to give users a chance to read the messages
output by "echo".
slowpaste msec
Define the speed at which text is inserted into the cur-
rent window by the paste ("C-a ]") command. If the slow-
paste value is nonzero text is written character by char-
acter. screen will make a pause of msec milliseconds
after each single character write to allow the application
to process its input. Only use slowpaste if your underly-
ing system exposes flow control problems while pasting
large amounts of text.
source file
Read and execute commands from file file. Source commands
may be nested to a maximum recursion level of ten. If file
is not an absolute path and screen is already processing a
source command, the parent directory of the running source
command file is used to search for the new command file
before screen's current directory.
Note that termcap/terminfo/termcapinfo commands only work
at startup and reattach time, so they must be reached via
the default screenrc files to have an effect.
sorendition [attr [color]]
Change the way screen does highlighting for text marking
and printing messages. See the "STRING ESCAPES" chapter
for the syntax of the modifiers. The default is currently
"=s dd" (standout, default colors).
split
Split the current region into two new ones. All regions on
the display are resized to make room for the new region.
The blank window is displayed on the new region. Use the
"remove" or the "only" command to delete regions.
startup_message on|off
Select whether you want to see the copyright notice during
startup. Default is `on', as you probably noticed.
stuff string
Stuff the string string in the input buffer of the current
window. This is like the "paste" command but with much
less overhead. You cannot paste large buffers with the
"stuff" command. It is most useful for key bindings. See
also "bindkey".
su [username [password [password2]]
Substitute the user of a display. The command prompts for
all parameters that are omitted. If passwords are speci-
fied as parameters, they have to be specified un-crypted.
The first password is matched against the systems passwd
database, the second password is matched against the
screen password as set with the commands "acladd" or
"password". "Su" may be useful for the screen administra-
tor to test multiuser setups. When the identification
fails, the user has access to the commands available for
user nobody. These are "detach", "license", "version",
"help" and "displays".
suspend
Suspend screen. The windows are in the `detached' state,
while screen is suspended. This feature relies on the
shell being able to do job control.
term term
In each window's environment screen opens, the $TERM vari-
able is set to "screen" by default. But when no descrip-
tion for "screen" is installed in the local termcap or
terminfo data base, you set $TERM to - say - "vt100". This
won't do much harm, as screen is VT100/ANSI compatible.
The use of the "term" command is discouraged for non-
default purpose. That is, one may want to specify special
$TERM settings (e.g. vt100) for the next "screen rlogin
othermachine" command. Use the command "screen -T vt100
rlogin othermachine" rather than setting and resetting the
default.
termcap term terminal-tweaks [window-tweaks]
terminfo term terminal-tweaks [window-tweaks]
termcapinfo term terminal-tweaks [window-tweaks]
Use this command to modify your terminal's termcap entry
without going through all the hassles involved in creating
a custom termcap entry. Plus, you can optionally cus-
tomize the termcap generated for the windows. You have to
place these commands in one of the screenrc startup files,
as they are meaningless once the terminal emulator is
booted.
If your system works uses the terminfo database rather
than termcap, screen will understand the `terminfo' com-
mand, which has the same effects as the `termcap' command.
Two separate commands are provided, as there are subtle
syntactic differences, e.g. when parameter interpolation
(using `%') is required. Note that termcap names of the
capabilities have to be used with the `terminfo' command.
In many cases, where the arguments are valid in both ter-
minfo and termcap syntax, you can use the command `term-
capinfo', which is just a shorthand for a pair of `term-
cap' and `terminfo' commands with identical arguments.
The first argument specifies which terminal(s) should be
affected by this definition. You can specify multiple
terminal names by separating them with `|'s. Use `*' to
match all terminals and `vt*' to match all terminals that
begin with "vt".
Each tweak argument contains one or more termcap defines
(separated by `:'s) to be inserted at the start of the
appropriate termcap entry, enhancing it or overriding
existing values. The first tweak modifies your terminal's
termcap, and contains definitions that your terminal uses
to perform certain functions. Specify a null string to
leave this unchanged (e.g. ''). The second (optional)
tweak modifies all the window termcaps, and should contain
definitions that screen understands (see the "VIRTUAL TER-
MINAL" section).
Some examples:
termcap xterm* LP:hs@
Informs screen that all terminals that begin with `xterm'
have firm auto-margins that allow the last position on the
screen to be updated (LP), but they don't really have a
status line (no 'hs' - append `@' to turn entries off).
Note that we assume `LP' for all terminal names that start
with "vt", but only if you don't specify a termcap command
for that terminal.
termcap vt* LP
termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l
Specifies the firm-margined `LP' capability for all termi-
nals that begin with `vt', and the second line will also
add the escape-sequences to switch into (Z0) and back out
of (Z1) 132-character-per-line mode if this is a VT102 or
VT220. (You must specify Z0 and Z1 in your termcap to use
the width-changing commands.)
termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4
This leaves your vt100 termcap alone and adds the function
key labels to each window's termcap entry.
termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P
Takes a h19 or z19 termcap and turns off auto-margins
(am@) and enables the insert mode (im) and end-insert (ei)
capabilities (the `@' in the `im' string is after the `=',
so it is part of the string). Having the `im' and `ei'
definitions put into your terminal's termcap will cause
screen to automatically advertise the character-insert
capability in each window's termcap. Each window will
also get the delete-character capability (dc) added to its
termcap, which screen will translate into a line-update
for the terminal (we're pretending it doesn't support
character deletion).
If you would like to fully specify each window's termcap
entry, you should instead set the $SCREENCAP variable
prior to running screen. See the discussion on the "VIR-
TUAL TERMINAL" in this manual, and the termcap(5) man page
for more information on termcap definitions.
time [string]
Uses the message line to display the time of day, the host
name, and the load averages over 1, 5, and 15 minutes (if
this is available on your system). For window specific
information use "info".
If a string is specified, it changes the format of the
time report like it is described in the "STRING ESCAPES"
chapter. Screen uses a default of "%c:%s %M %d %H%? %l%?".
title [windowtitle]
Set the name of the current window to windowtitle. If no
name is specified, screen prompts for one. This command
was known as `aka' in previous releases.
unsetenv var
Unset an environment variable.
utf8 [on|off [on|off]]
Change the encoding used in the current window. If utf8 is
enabled, the strings sent to the window will be UTF-8
encoded and vice versa. Omitting the parameter toggles the
setting. If a second parameter is given, the display's
encoding is also changed (this should rather be done with
screen's "-U" option). See also "defutf8", which changes
the default setting of a new window.
vbell [on|off]
Sets the visual bell setting for this window. Omitting the
parameter toggles the setting. If vbell is switched on,
but your terminal does not support a visual bell, a
`vbell-message' is displayed in the status line when the
bell character (^G) is received. Visual bell support of a
terminal is defined by the termcap variable `vb' (ter-
minfo: 'flash').
Per default, vbell is off, thus the audible bell is used.
See also `bell_msg'.
vbell_msg [message]
Sets the visual bell message. message is printed to the
status line if the window receives a bell character (^G),
vbell is set to "on", but the terminal does not support a
visual bell. The default message is "Wuff, Wuff!!".
Without parameter, the current message is shown.
vbellwait sec
Define a delay in seconds after each display of screen's
visual bell message. The default is 1 second.
verbose [on|off]
If verbose is switched on, the command name is echoed,
whenever a window is created (or resurrected from zombie
state). Default is off. Without parameter, the current
setting is shown.
version
Print the current version and the compile date in the sta-
tus line.
wall message
Write a message to all displays. The message will appear
in the terminal's status line.
width [-w|-d] [cols [lines]]
Toggle the window width between 80 and 132 columns or set
it to cols columns if an argument is specified. This
requires a capable terminal and the termcap entries "Z0"
and "Z1". See the "termcap" command for more information.
You can also specify a new height if you want to change
both values. The -w option tells screen to leave the dis-
play size unchanged and just set the window size, -d vice
versa.
windowlist [-b] | string [string] | title [title]
Display all windows in a table for visual window selec-
tion. The desired window can be selected via the standard
movement keys (see the "copy" command) and activated via
the return key. If the -b option is given, screen will
switch to the blank window before presenting the list, so
that the current window is also selectable.
The table format can be changed with the string and title
option, the title is displayed as table heading, while the
lines are made by using the string setting. The default
setting is "Num Name%=Flags" for the title and "%3n
%t%=%f" for the lines. See the "STRING ESCAPES" chapter
for more codes (e.g. color settings).
windows
Uses the message line to display a list of all the win-
dows. Each window is listed by number with the name of
process that has been started in the window (or its
title); the current window is marked with a `*'; the pre-
vious window is marked with a `-'; all the windows that
are "logged in" are marked with a `$'; a background window
that has received a bell is marked with a `!'; a back-
ground window that is being monitored and has had activity
occur is marked with an `@'; a window which has output
logging turned on is marked with `(L)'; windows occupied
by other users are marked with `&'; windows in the zombie
state are marked with `Z'. If this list is too long to
fit on the terminal's status line only the portion around
the current window is displayed.
wrap [on|off]
Sets the line-wrap setting for the current window. When
line-wrap is on, the second consecutive printable charac-
ter output at the last column of a line will wrap to the
start of the following line. As an added feature,
backspace (^H) will also wrap through the left margin to
the previous line. Default is `on'.
writebuf [-e encoding] [filename]
Writes the contents of the paste buffer to the specified
file, or the public accessible screen-exchange file if no
filename is given. This is thought of as a primitive means
of communication between screen users on the same host. If
an encoding is specified the paste buffer is recoded on
the fly to match the encoding. The filename can be set
with the bufferfile command and defaults to "/tmp/screen-
exchange".
writelock [on|off|auto]
In addition to access control lists, not all users may be
able to write to the same window at once. Per default,
writelock is in `auto' mode and grants exclusive input
permission to the user who is the first to switch to the
particular window. When he leaves the window, other users
may obtain the writelock (automatically). The writelock of
the current window is disabled by the command "writelock
off". If the user issues the command "writelock on" he
keeps the exclusive write permission while switching to
other windows.
xoff
xon
Insert a CTRL-s / CTRL-q character to the stdin queue of
the current window.
zombie [keys]
defzombie [keys]
Per default screen windows are removed from the window
list as soon as the windows process (e.g. shell) exits.
When a string of two keys is specified to the zombie com-
mand, `dead' windows will remain in the list. The kill
command may be used to remove such a window. Pressing the
first key in the dead window has the same effect. When
pressing the second key, screen will attempt to resurrect
the window. The process that was initially running in the
window will be launched again. Calling zombie without
parameters will clear the zombie setting, thus making win-
dows disappear when their process exits.
As the zombie-setting is manipulated globally for all win-
dows, this command should only be called defzombie. Until
we need this as a per window setting, the commands zombie
and defzombie are synonymous.
THE MESSAGE LINE
Screen displays informational messages and other diagnos-
tics in a message line. While this line is distributed to
appear at the bottom of the screen, it can be defined to
appear at the top of the screen during compilation. If
your terminal has a status line defined in its termcap,
screen will use this for displaying its messages, other-
wise a line of the current screen will be temporarily
overwritten and output will be momentarily interrupted.
The message line is automatically removed after a few sec-
onds delay, but it can also be removed early (on terminals
without a status line) by beginning to type.
The message line facility can be used by an application
running in the current window by means of the ANSI Privacy
message control sequence. For instance, from within the
shell, try something like:
echo '<esc>^Hello world from window '$WIN-
DOW'<esc>\\'
where '<esc>' is an escape, '^' is a literal up-arrow, and
'\\' turns into a single backslash.
WINDOW TYPES
Screen provides three different window types. New windows
are created with screen's screen command (see also the
entry in chapter "CUSTOMIZATION"). The first parameter to
the screen command defines which type of window is cre-
ated. The different window types are all special cases of
the normal type. They have been added in order to allow
screen to be used efficiently as a console multiplexer
with 100 or more windows.
o The normal window contains a shell (default, if no
parameter is given) or any other system command that
could be executed from a shell (e.g. slogin, etc...)
o If a tty (character special device) name (e.g.
"/dev/ttya") is specified as the first parameter, then
the window is directly connected to this device. This
window type is similar to "screen cu -l /dev/ttya".
Read and write access is required on the device node,
an exclusive open is attempted on the node to mark the
connection line as busy. An optional parameter is
allowed consisting of a comma separated list of flags
in the notation used by stty(1):
<baud_rate>
Usually 300, 1200, 9600 or 19200. This affects
transmission as well as receive speed.
cs8 or cs7
Specify the transmission of eight (or seven)
bits per byte.
ixon or -ixon
Enables (or disables) software flow-control
(CTRL-S/CTRL-Q) for sending data.
ixoff or -ixon
Enables (or disables) software flow-control for
receiving data.
istrip or -istrip
Clear (or keep) the eight bit in each received
byte.
You may want to specify as many of these options as
applicable. Unspecified options cause the terminal
driver to make up the parameter values of the connec-
tion. These values are system dependant and may be in
defaults or values saved from a previous connection.
For tty windows, the info command shows some of the
modem control lines in the status line. These may
include `RTS', `CTS', 'DTR', `DSR', `CD' and more.
This depends on the available ioctl()'s and system
header files as well as the on the physical capabili-
ties of the serial board. Signals that are logical low
(inactive) have their name preceded by an exclamation
mark (!), otherwise the signal is logical high
(active). Signals not supported by the hardware but
available to the ioctl() interface are usually shown
low.
When the CLOCAL status bit is true, the whole set of
modem signals is placed inside curly braces ({ and }).
When the CRTSCTS or TIOCSOFTCAR bit is set, the signals
`CTS' or `CD' are shown in parenthesis, respectively.
For tty windows, the command break causes the Data
transmission line (TxD) to go low for a specified
period of time. This is expected to be interpreted as
break signal on the other side. No data is sent and no
modem control line is changed when a break is issued.
o If the first parameter is "//telnet", the second param-
eter is expected to be a host name, and an optional
third parameter may specify a TCP port number (default
decimal 23). Screen will connect to a server listening
on the remote host and use the telnet protocol to com-
municate with that server.
For telnet windows, the command info shows details
about the connection in square brackets ([ and ]) at
the end of the status line.
b BINARY. The connection is in binary mode.
e ECHO. Local echo is disabled.
c SGA. The connection is in `character mode'
(default: `line mode').
t TTYPE. The terminal type has been requested by
the remote host. Screen sends the name "screen"
unless instructed otherwise (see also the com-
mand `term').
w NAWS. The remote site is notified about window
size changes.
f LFLOW. The remote host will send flow control
information. (Ignored at the moment.)
Additional flags for debugging are x, t and n
(XDISPLOC, TSPEED and NEWENV).
For telnet windows, the command break sends the telnet
code IAC BREAK (decimal 243) to the remote host.
This window type is only available if screen was com-
piled with the BUILTIN_TELNET option defined.
STRING ESCAPES
Screen provides an escape mechanism to insert information
like the current time into messages or file names. The
escape character is '%' with one exception: inside of a
window's hardstatus '^%' ('^E') is used instead.
Here is the full list of supported escapes:
% the escape character itself
a either 'am' or 'pm'
A either 'AM' or 'PM'
c current time HH:MM in 24h format
C current time HH:MM in 12h format
d day number
D weekday name
f flags of the window
F sets %? to true if the window has the focus
h hardstatus of the window
H hostname of the system
l current load of the system
m month number
M month name
n window number
s seconds
t window title
u all other users on this window
w all window numbers and names. With '-' quailifier:
up to the current window; with '+' qualifier:
starting with the window after the current one.
W all window numbers and names except the current one
y last two digits of the year number
Y full year number
? the part to the next '%?' is displayed only if a
'%' escape inside the part expands to a non-empty
string
: else part of '%?'
= pad the string to the display's width (like TeX's
hfill). If a number is specified, pad to the per-
centage of the window's width. A '0' qualifier
tells screen to treat the number as absolute posi-
tion. You can specify to pad relative to the last
absolute pad position by adding a '+' qualifier or
to pad relative to the right margin by using '-'.
The padding truncates the string if the specified
position lies before the current position. Add the
'L' qualifier to change this.
< same as '%=' but just do truncation, do not fill
with spaces
> mark the current text position for the next trunca-
tion. When screen needs to do truncation, it tries
to do it in a way that the marked position gets
moved to the specified percentage of the output
area. (The area starts from the last absolute pad
position and ends with the position specified by
the truncation operator.) The 'L' qualifier tells
screen to mark the truncated parts with '...'.
{ attribute/color modifier string terminated by the
next "}"
` Substitute with the output of a 'backtick' command.
The length qualifier is misused to identify one of
the commands.
The 'c' and 'C' escape may be qualified with a '0' to make
screen use zero instead of space as fill character. The
'0' qualifier also makes the '=' escape use absolute posi-
tions. The 'n' and '=' escapes understand a length quali-
fier (e.g. '%3n'), 'D' and 'M' can be prefixed with 'L' to
generate long names, 'w' and 'W' also show the window
flags if 'L' is given.
An attribute/color modifier is is used to change the
attributes or the color settings. Its format is
"[attribute modifier] [color description]". The attribute
modifier must be prefixed by a change type indicator if it
can be confused with a color desciption. The following
change types are known:
+ add the specified set to the current attributes
- remove the set from the current attributes
! invert the set in the current attributes
= change the current attributes to the specified set
The attribute set can either be specified as a hexadecimal
number or a combination of the following letters:
d dim
u underline
b bold
r reverse
s standout
B blinking
Colors are coded either as a hexadecimal number or two
letters specifying the desired background and foreground
color (in that order). The following colors are known:
k black
r red
g green
y yellow
b blue
m magenta
c cyan
w white
d default color
. leave color unchanged
The capitalized versions of the letter specify bright col-
ors. You can also use the pseudo-color 'i' to set just the
brightness and leave the color unchanged.
A one digit/letter color description is treated as fore-
ground or background color dependant on the current
attributes: if reverse mode is set, the background color
is changed instead of the foreground color. If you don't
like this, prefix the color with a ".". If you want the
same behaviour for two-letter color descriptions, also
prefix them with a ".".
As a special case, "%{-}" restores the attributes and col-
ors that were set before the last change was made (i.e.
pops one level of the color-change stack).
Examples:
"G" set color to bright green
"+b r" use bold red
"= yd" clear all attributes, write in default color on
yellow background.
%-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%<
The available windows centered at the current win-
dow and truncated to the available width. The cur-
rent window is displayed white on blue. This can
be used with "hardstatus alwayslastline".
%?%F%{.R.}%?%3n %t%? [%h]%?
The window number and title and the window's hard-
status, if one is set. Also use a red background
if this is the active focus. Useful for "caption
string".
FLOW-CONTROL
Each window has a flow-control setting that determines how
screen deals with the XON and XOFF characters (and perhaps
the interrupt character). When flow-control is turned
off, screen ignores the XON and XOFF characters, which
allows the user to send them to the current program by
simply typing them (useful for the emacs editor, for
instance). The trade-off is that it will take longer for
output from a "normal" program to pause in response to an
XOFF. With flow-control turned on, XON and XOFF charac-
ters are used to immediately pause the output of the cur-
rent window. You can still send these characters to the
current program, but you must use the appropriate two-
character screen commands (typically "C-a q" (xon) and "C-
a s" (xoff)). The xon/xoff commands are also useful for
typing C-s and C-q past a terminal that intercepts these
characters.
Each window has an initial flow-control value set with
either the -f option or the "defflow" .screenrc command.
Per default the windows are set to automatic flow-switch-
ing. It can then be toggled between the three states
'fixed on', 'fixed off' and 'automatic' interactively with
the "flow" command bound to "C-a f".
The automatic flow-switching mode deals with flow control
using the TIOCPKT mode (like "rlogin" does). If the tty
driver does not support TIOCPKT, screen tries to find out
the right mode based on the current setting of the appli-
cation keypad - when it is enabled, flow-control is turned
off and visa versa. Of course, you can still manipulate
flow-control manually when needed.
If you're running with flow-control enabled and find that
pressing the interrupt key (usually C-c) does not inter-
rupt the display until another 6-8 lines have scrolled by,
try running screen with the "interrupt" option (add the
"interrupt" flag to the "flow" command in your .screenrc,
or use the -i command-line option). This causes the out-
put that screen has accumulated from the interrupted pro-
gram to be flushed. One disadvantage is that the virtual
terminal's memory contains the non-flushed version of the
output, which in rare cases can cause minor inaccuracies
in the output. For example, if you switch screens and
return, or update the screen with "C-a l" you would see
the version of the output you would have gotten without
"interrupt" being on. Also, you might need to turn off
flow-control (or use auto-flow mode to turn it off auto-
matically) when running a program that expects you to type
the interrupt character as input, as it is possible to
interrupt the output of the virtual terminal to your phys-
ical terminal when flow-control is enabled. If this hap-
pens, a simple refresh of the screen with "C-a l" will
restore it. Give each mode a try, and use whichever mode
you find more comfortable.
TITLES (naming windows)
You can customize each window's name in the window display
(viewed with the "windows" command (C-a w)) by setting it
with one of the title commands. Normally the name dis-
played is the actual command name of the program created
in the window. However, it is sometimes useful to distin-
guish various programs of the same name or to change the
name on-the-fly to reflect the current state of the win-
dow.
The default name for all shell windows can be set with the
"shelltitle" command in the .screenrc file, while all
other windows are created with a "screen" command and thus
can have their name set with the -t option. Interac-
tively, there is the title-string escape-sequence
(<esc>kname<esc>\) and the "title" command (C-a A). The
former can be output from an application to control the
window's name under software control, and the latter will
prompt for a name when typed. You can also bind pre-
defined names to keys with the "title" command to set
things quickly without prompting.
Finally, screen has a shell-specific heuristic that is
enabled by setting the window's name to "search|name" and
arranging to have a null title escape-sequence output as a
part of your prompt. The search portion specifies an end-
of-prompt search string, while the name portion specifies
the default shell name for the window. If the name ends
in a `:' screen will add what it believes to be the cur-
rent command running in the window to the end of the win-
dow's shell name (e.g. "name:cmd"). Otherwise the current
command name supersedes the shell name while it is run-
ning.
Here's how it works: you must modify your shell prompt to
output a null title-escape-sequence (<esc>k<esc>\) as a
part of your prompt. The last part of your prompt must be
the same as the string you specified for the search por-
tion of the title. Once this is set up, screen will use
the title-escape-sequence to clear the previous command
name and get ready for the next command. Then, when a
newline is received from the shell, a search is made for
the end of the prompt. If found, it will grab the first
word after the matched string and use it as the command
name. If the command name begins with either '!', '%', or
'^' screen will use the first word on the following line
(if found) in preference to the just-found name. This
helps csh users get better command names when using job
control or history recall commands.
Here's some .screenrc examples:
screen-t top 2 nice top
Adding this line to your .screenrc would start a nice-d
version of the "top" command in window 2 named "top"
rather than "nice".
shelltitle '> |csh'
screen 1
These commands would start a shell with the given shellti-
tle. The title specified is an auto-title that would
expect the prompt and the typed command to look something
like the following:
/usr/joe/src/dir> trn
(it looks after the '> ' for the command name). The win-
dow status would show the name "trn" while the command was
running, and revert to "csh" upon completion.
bind R screen-t '% |root:' su
Having this command in your .screenrc would bind the key
sequence "C-a R" to the "su" command and give it an auto-
title name of "root:". For this auto-title to work, the
screen could look something like this:
% !em
emacs file.c
Here the user typed the csh history command "!em" which
ran the previously entered "emacs" command. The window
status would show "root:emacs" during the execution of the
command, and revert to simply "root:" at its completion.
bind o title
bind E title ""
bind u title (unknown)
The first binding doesn't have any arguments, so it would
prompt you for a title. when you type "C-a o". The second
binding would clear an auto-title's current setting (C-a
E). The third binding would set the current window's
title to "(unknown)" (C-a u).
One thing to keep in mind when adding a null title-escape-
sequence to your prompt is that some shells (like the csh)
count all the non-control characters as part of the
prompt's length. If these invisible characters aren't a
multiple of 8 then backspacing over a tab will result in
an incorrect display. One way to get around this is to
use a prompt like this:
set prompt='^[[0000m^[k^[\% '
The escape-sequence "<esc>[0000m" not only normalizes the
character attributes, but all the zeros round the length
of the invisible characters up to 8. Bash users will
probably want to echo the escape sequence in the
PROMPT_COMMAND:
PROMPT_COMMAND='echo -n -e "\033k\033\134"'
(I used "134" to output a `\' because of a bug in bash
v1.04).
THE VIRTUAL TERMINAL
Each window in a screen session emulates a VT100 terminal,
with some extra functions added. The VT100 emulator is
hard-coded, no other terminal types can be emulated.
Usually screen tries to emulate as much of the VT100/ANSI
standard as possible. But if your terminal lacks certain
capabilities, the emulation may not be complete. In these
cases screen has to tell the applications that some of the
features are missing. This is no problem on machines using
termcap, because screen can use the $TERMCAP variable to
customize the standard screen termcap.
But if you do a rlogin on another machine or your machine
supports only terminfo this method fails. Because of this,
screen offers a way to deal with these cases. Here is how
it works:
When screen tries to figure out a terminal name for
itself, it first looks for an entry named "screen.<term>",
where <term> is the contents of your $TERM variable. If
no such entry exists, screen tries "screen" (or "screen-w"
if the terminal is wide (132 cols or more)). If even this
entry cannot be found, "vt100" is used as a substitute.
The idea is that if you have a terminal which doesn't sup-
port an important feature (e.g. delete char or clear to
EOS) you can build a new termcap/terminfo entry for screen
(named "screen.<dumbterm>") in which this capability has
been disabled. If this entry is installed on your machines
you are able to do a rlogin and still keep the correct
termcap/terminfo entry. The terminal name is put in the
$TERM variable of all new windows. Screen also sets the
$TERMCAP variable reflecting the capabilities of the vir-
tual terminal emulated. Notice that, however, on machines
using the terminfo database this variable has no effect.
Furthermore, the variable $WINDOW is set to the window
number of each window.
The actual set of capabilities supported by the virtual
terminal depends on the capabilities supported by the
physical terminal. If, for instance, the physical termi-
nal does not support underscore mode, screen does not put
the `us' and `ue' capabilities into the window's $TERMCAP
variable, accordingly. However, a minimum number of capa-
bilities must be supported by a terminal in order to run
screen; namely scrolling, clear screen, and direct cursor
addressing (in addition, screen does not run on hardcopy
terminals or on terminals that over-strike).
Also, you can customize the $TERMCAP value used by screen
by using the "termcap" .screenrc command, or by defining
the variable $SCREENCAP prior to startup. When the is
latter defined, its value will be copied verbatim into
each window's $TERMCAP variable. This can either be the
full terminal definition, or a filename where the terminal
"screen" (and/or "screen-w") is defined.
Note that screen honors the "terminfo" .screenrc command
if the system uses the terminfo database rather than term-
cap.
When the boolean `G0' capability is present in the termcap
entry for the terminal on which screen has been called,
the terminal emulation of screen supports multiple charac-
ter sets. This allows an application to make use of, for
instance, the VT100 graphics character set or national
character sets. The following control functions from ISO
2022 are supported: lock shift G0 (SI), lock shift G1
(SO), lock shift G2, lock shift G3, single shift G2, and
single shift G3. When a virtual terminal is created or
reset, the ASCII character set is designated as G0 through
G3. When the `G0' capability is present, screen evaluates
the capabilities `S0', `E0', and `C0' if present. `S0' is
the sequence the terminal uses to enable and start the
graphics character set rather than SI. `E0' is the corre-
sponding replacement for SO. `C0' gives a character by
character translation string that is used during semi-
graphics mode. This string is built like the `acsc' ter-
minfo capability.
When the `po' and `pf' capabilities are present in the
terminal's termcap entry, applications running in a screen
window can send output to the printer port of the termi-
nal. This allows a user to have an application in one
window sending output to a printer connected to the termi-
nal, while all other windows are still active (the printer
port is enabled and disabled again for each chunk of out-
put). As a side-effect, programs running in different
windows can send output to the printer simultaneously.
Data sent to the printer is not displayed in the window.
The info command displays a line starting `PRIN' while the
printer is active.
Screen maintains a hardstatus line for every window. If a
window gets selected, the display's hardstatus will be
updated to match the window's hardstatus line. If the dis-
play has no hardstatus the line will be displayed as a
standard screen message. The hardstatus line can be
changed with the ANSI Application Program Command (APC):
"ESC_<string>ESC\". As a convenience for xterm users the
sequence "ESC]0..2;<string>^G" is also accepted.
Some capabilities are only put into the $TERMCAP variable
of the virtual terminal if they can be efficiently imple-
mented by the physical terminal. For instance, `dl'
(delete line) is only put into the $TERMCAP variable if
the terminal supports either delete line itself or
scrolling regions. Note that this may provoke confusion,
when the session is reattached on a different terminal, as
the value of $TERMCAP cannot be modified by parent pro-
cesses.
The "alternate screen" capability is not enabled by
default. Set the altscreen .screenrc command to enable
it.
The following is a list of control sequences recognized by
screen. "(V)" and "(A)" indicate VT100-specific and ANSI-
or ISO-specific functions, respectively.
ESC E Next Line
ESC D Index
ESC M Reverse Index
ESC H Horizontal Tab Set
ESC Z Send VT100 Identification
String
ESC 7 (V) Save Cursor and Attributes
ESC 8 (V) Restore Cursor and Attributes
ESC [s (A) Save Cursor and Attributes
ESC [u (A) Restore Cursor and Attributes
ESC c Reset to Initial State
ESC g Visual Bell
ESC Pn p Cursor Visibility (97801)
Pn = 6 Invisible
7 Visible
ESC = (V) Application Keypad Mode
ESC > (V) Numeric Keypad Mode
ESC # 8 (V) Fill Screen with E's
ESC \ (A) String Terminator
ESC ^ (A) Privacy Message String (Message
Line)
ESC ! Global Message String (Message
Line)
ESC k A.k.a. Definition String
ESC P (A) Device Control String. Outputs
a string directly to the host
terminal without interpreta-
tion.
ESC _ (A) Application Program Command
(Hardstatus)
ESC ] 0 ; string ^G (A) Operating System Command (Hard-
status, xterm title hack)
ESC ] 83 ; cmd ^G (A) Execute screen command. This
only works if multi-user sup-
port is compiled into screen.
The pseudo-user ":window:" is
used to check the access con-
trol list. Use "addacl :window:
-rwx #?" to create a user with
no rights and allow only the
needed commands.
Control-N (A) Lock Shift G1 (SO)
Control-O (A) Lock Shift G0 (SI)
ESC n (A) Lock Shift G2
ESC o (A) Lock Shift G3
ESC N (A) Single Shift G2
ESC O (A) Single Shift G3
ESC ( Pcs (A) Designate character set as G0
ESC ) Pcs (A) Designate character set as G1
ESC * Pcs (A) Designate character set as G2
ESC + Pcs (A) Designate character set as G3
ESC [ Pn ; Pn H Direct Cursor Addressing
ESC [ Pn ; Pn f same as above
ESC [ Pn J Erase in Display
Pn = None or 0 From Cursor to End of Screen
1 From Beginning of Screen to
Cursor
2 Entire Screen
ESC [ Pn K Erase in Line
Pn = None or 0 From Cursor to End of Line
1 From Beginning of Line to Cur-
sor
2 Entire Line
ESC [ Pn X Erase character
ESC [ Pn A Cursor Up
ESC [ Pn B Cursor Down
ESC [ Pn C Cursor Right
ESC [ Pn D Cursor Left
ESC [ Pn E Cursor next line
ESC [ Pn F Cursor previous line
ESC [ Pn G Cursor horizontal position
ESC [ Pn ` same as above
ESC [ Pn d Cursor vertical position
ESC [ Ps ;...; Ps m Select Graphic Rendition
Ps = None or 0 Default Rendition
1 Bold
2 (A) Faint
3 (A) Standout Mode (ANSI: Itali-
cized)
4 Underlined
5 Blinking
7 Negative Image
22 (A) Normal Intensity
23 (A) Standout Mode off (ANSI: Itali-
cized off)
24 (A) Not Underlined
25 (A) Not Blinking
27 (A) Positive Image
30 (A) Foreground Black
31 (A) Foreground Red
32 (A) Foreground Green
33 (A) Foreground Yellow
34 (A) Foreground Blue
35 (A) Foreground Magenta
36 (A) Foreground Cyan
37 (A) Foreground White
39 (A) Foreground Default
40 (A) Background Black
...
49 (A) Background Default
ESC [ Pn g Tab Clear
Pn = None or 0 Clear Tab at Current Position
3 Clear All Tabs
ESC [ Pn ; Pn r (V) Set Scrolling Region
ESC [ Pn I (A) Horizontal Tab
ESC [ Pn Z (A) Backward Tab
ESC [ Pn L (A) Insert Line
ESC [ Pn M (A) Delete Line
ESC [ Pn @ (A) Insert Character
ESC [ Pn P (A) Delete Character
ESC [ Pn S Scroll Scrolling Region Up
ESC [ Pn T Scroll Scrolling Region Down
ESC [ Pn ^ same as above
ESC [ Ps ;...; Ps h Set Mode
ESC [ Ps ;...; Ps l Reset Mode
Ps = 4 (A) Insert Mode
20 (A) Automatic Linefeed Mode
34 Normal Cursor Visibility
?1 (V) Application Cursor Keys
?3 (V) Change Terminal Width to 132
columns
?5 (V) Reverse Video
?6 (V) Origin Mode
?7 (V) Wrap Mode
?9 X10 mouse tracking
?25 (V) Visible Cursor
?47 Alternate Screen (old xterm
code)
?1000 (V) VT200 mouse tracking
?1047 Alternate Screen (new xterm
code)
?1049 Alternate Screen (new xterm
code)
ESC [ 5 i (A) Start relay to printer (ANSI
Media Copy)
ESC [ 4 i (A) Stop relay to printer (ANSI
Media Copy)
ESC [ 8 ; Ph ; Pw t Resize the window to `Ph' lines
and `Pw' columns (SunView spe-
cial)
ESC [ c Send VT100 Identification
String
ESC [ x Send Terminal Parameter Report
ESC [ > c Send VT220 Secondary Device
Attributes String
ESC [ 6 n Send Cursor Position Report
INPUT TRANSLATION
In order to do a full VT100 emulation screen has to detect
that a sequence of characters in the input stream was gen-
erated by a keypress on the user's keyboard and insert the
VT100 style escape sequence. Screen has a very flexible
way of doing this by making it possible to map arbitrary
commands on arbitrary sequences of characters. For stan-
dard VT100 emulation the command will always insert a
string in the input buffer of the window (see also command
stuff in the command table). Because the sequences gener-
ated by a keypress can change after a reattach from a dif-
ferent terminal type, it is possible to bind commands to
the termcap name of the keys. Screen will insert the cor-
rect binding after each reattach. See the bindkey command
for further details on the syntax and examples.
Here is the table of the default key bindings. (A) means
that the command is executed if the keyboard is switched
into application mode.
Key name Termcap name Command
______________________________________________________
Cursor up ku stuff \033[A
stuff \033OA (A)
Cursor down kd stuff \033[B
stuff \033OB (A)
Cursor right kr stuff \033[C
stuff \033OC (A)
Cursor left kl stuff \033[D
stuff \033OD (A)
Function key 0 k0 stuff \033[10~
Function key 1 k1 stuff \033OP
Function key 2 k2 stuff \033OQ
Function key 3 k3 stuff \033OR
Function key 4 k4 stuff \033OS
Function key 5 k5 stuff \033[15~
Function key 6 k6 stuff \033[17~
Function key 7 k7 stuff \033[18~
Function key 8 k8 stuff \033[19~
Function key 9 k9 stuff \033[20~
Function key 10 k; stuff \033[21~
Function key 11 F1 stuff \033[23~
Function key 12 F2 stuff \033[24~
Home kh stuff \033[1~
End kH stuff \033[4~
Insert kI stuff \033[2~
Delete kD stuff \033[3~
Page up kP stuff \033[5~
Page down kN stuff \033[6~
Keypad 0 f0 stuff 0
stuff \033Op (A)
Keypad 1 f1 stuff 1
stuff \033Oq (A)
Keypad 2 f2 stuff 2
stuff \033Or (A)
Keypad 3 f3 stuff 3
stuff \033Os (A)
Keypad 4 f4 stuff 4
stuff \033Ot (A)
Keypad 5 f5 stuff 5
stuff \033Ou (A)
Keypad 6 f6 stuff 6
stuff \033Ov (A)
Keypad 7 f7 stuff 7
stuff \033Ow (A)
Keypad 8 f8 stuff 8
stuff \033Ox (A)
Keypad 9 f9 stuff 9
stuff \033Oy (A)
Keypad + f+ stuff +
stuff \033Ok (A)
Keypad - f- stuff -
stuff \033Om (A)
Keypad * f* stuff *
stuff \033Oj (A)
Keypad / f/ stuff /
stuff \033Oo (A)
Keypad = fq stuff =
stuff \033OX (A)
Keypad . f. stuff .
stuff \033On (A)
Keypad , f, stuff ,
stuff \033Ol (A)
Keypad enter fe stuff \015
stuff \033OM (A)
SPECIAL TERMINAL CAPABILITIES
The following table describes all terminal capabilities
that are recognized by screen and are not in the term-
cap(5) manual. You can place these capabilities in your
termcap entries (in `/etc/termcap') or use them with the
commands `termcap', `terminfo' and `termcapinfo' in your
screenrc files. It is often not possible to place these
capabilities in the terminfo database.
LP (bool) Terminal has VT100 style margins (`magic mar-
gins'). Note that this capability is obsolete
because screen uses the standard 'xn'
instead.
Z0 (str) Change width to 132 columns.
Z1 (str) Change width to 80 columns.
WS (str) Resize display. This capability has the
desired width and height as arguments. Sun-
View(tm) example: '\E[8;%d;%dt'.
NF (bool) Terminal doesn't need flow control. Send ^S
and ^Q direct to the application. Same as
'flow off'. The opposite of this capability
is 'nx'.
G0 (bool) Terminal can deal with ISO 2022 font selec-
tion sequences.
S0 (str) Switch charset 'G0' to the specified charset.
Default is '\E(%.'.
E0 (str) Switch charset 'G0' back to standard charset.
Default is '\E(B'.
C0 (str) Use the string as a conversion table for font
'0'. See the 'ac' capability for more
details.
CS (str) Switch cursor-keys to application mode.
CE (str) Switch cursor-keys back to normal mode.
AN (bool) Turn on autonuke. See the 'autonuke' command
for more details.
OL (num) Set the output buffer limit. See the 'obu-
flimit' command for more details.
KJ (str) Set the encoding of the terminal. See the
'encoding' command for valid encodings.
AF (str) Change character foreground color in an ANSI
conform way. This capability will almost
always be set to '\E[3%dm' ('\E[3%p1%dm' on
terminfo machines).
AB (str) Same as 'AF', but change background color.
AX (bool) Does understand ANSI set default fg/bg color
(\E[39m / \E[49m).
XC (str) Describe a translation of characters to
strings depending on the current font. More
details follow in the next section.
XT (bool) Terminal understands special xterm sequences
(OSC, mouse tracking).
C8 (bool) Terminal needs bold to display high-intensity
colors (e.g. Eterm).
TF (bool) Add missing capabilities to the termcap/info
entry. (Set by default).
CHARACTER TRANSLATION
Screen has a powerful mechanism to translate characters to
arbitrary strings depending on the current font and termi-
nal type. Use this feature if you want to work with a
common standard character set (say ISO8851-latin1) even on
terminals that scatter the more unusual characters over
several national language font pages.
Syntax:
XC=<charset-mapping>{,,<charset-mapping>}
<charset-mapping> := <designator><template>{,<mapping>}
<mapping> := <char-to-be-mapped><template-arg>
The things in braces may be repeated any number of times.
A <charset-mapping> tells screen how to map characters in
font <designator> ('B': Ascii, 'A': UK, 'K': german, etc.)
to strings. Every <mapping> describes to what string a
single character will be translated. A template mechanism
is used, as most of the time the codes have a lot in com-
mon (for example strings to switch to and from another
charset). Each occurrence of '%' in <template> gets sub-
stituted with the <template-arg> specified together with
the character. If your strings are not similar at all,
then use '%' as a template and place the full string in
<template-arg>. A quoting mechanism was added to make it
possible to use a real '%'. The '\' character quotes the
special characters '\', '%', and ','.
Here is an example:
termcap hp700 'XC=B\E(K%\E(B,\304[,\326\\\\,\334]'
This tells screen how to translate ISOlatin1 (charset 'B')
upper case umlaut characters on a hp700 terminal that has
a german charset. '\304' gets translated to '\E(K[\E(B'
and so on. Note that this line gets parsed *three* times
before the internal lookup table is built, therefore a lot
of quoting is needed to create a single '\'.
Another extension was added to allow more emulation: If a
mapping translates the unquoted '%' char, it will be sent
to the terminal whenever screen switches to the corre-
sponding <designator>. In this special case the template
is assumed to be just '%' because the charset switch
sequence and the character mappings normally haven't much
in common.
This example shows one use of the extension:
termcap xterm 'XC=K%,%\E(B,[\304,\\\\\326,]\334'
Here, a part of the german ('K') charset is emulated on an
xterm. If screen has to change to the 'K' charset, '\E(B'
will be sent to the terminal, i.e. the ASCII charset is
used instead. The template is just '%', so the mapping is
straightforward: '[' to '\304', '\' to '\326', and ']' to
'\334'.
ENVIRONMENT
COLUMNS Number of columns on the terminal (over-
rides termcap entry).
HOME Directory in which to look for .screenrc.
LINES Number of lines on the terminal (overrides
termcap entry).
LOCKPRG Screen lock program.
NETHACKOPTIONS Turns on nethack option.
PATH Used for locating programs to run.
SCREENCAP For customizing a terminal's TERMCAP value.
SCREENDIR Alternate socket directory.
SCREENRC Alternate user screenrc file.
SHELL Default shell program for opening windows
(default "/bin/sh").
STY Alternate socket name.
SYSSCREENRC Alternate system screenrc file.
TERM Terminal name.
TERMCAP Terminal description.
WINDOW Window number of a window (at creation
time).
FILES
.../screen-3.?.??/etc/screenrc
.../screen-3.?.??/etc/etcscreenrc Examples in the screen
distribution package for
private and global ini-
tialization files.
$SYSSCREENRC
/usr/local/etc/screenrc screen initialization
commands
$SCREENRC
$HOME/.screenrc Read in after
/usr/local/etc/screenrc
$SCREENDIR/S-<login>
/local/screens/S-<login> Socket directories
(default)
/usr/tmp/screens/S-<login> Alternate socket direc-
tories.
<socket directory>/.termcap Written by the "termcap"
output function
/usr/tmp/screens/screen-exchange or
/tmp/screen-exchange screen `interprocess
communication buffer'
hardcopy.[0-9] Screen images created by
the hardcopy function
screenlog.[0-9] Output log files created
by the log function
/usr/lib/terminfo/?/* or
/etc/termcap Terminal capability
databases
/etc/utmp Login records
$LOCKPRG Program that locks a
terminal.
SEE ALSOtermcap(5), utmp(5), vi(1), captoinfo(1), tic(1)AUTHORS
Originally created by Oliver Laumann, this latest version
was produced by Wayne Davison, Juergen Weigert and Michael
Schroeder.
COPYLEFT
Copyright (C) 1993-2003
Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
Copyright (C) 1987 Oliver Laumann
This program is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public
License as published by the Free Software Foundation;
either version 2, or (at your option) any later version.
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public
License along with this program (see the file COPYING); if
not, write to the Free Software Foundation, Inc., 59 Tem-
ple Place - Suite 330, Boston, MA 02111-1307, USA
CONTRIBUTORS
Ken Beal (kbeal@amber.ssd.csd.harris.com),
Rudolf Koenig (rfkoenig@immd4.informatik.uni-erlangen.de),
Toerless Eckert (eckert@immd4.informatik.uni-erlangen.de),
Wayne Davison (davison@borland.com),
Patrick Wolfe (pat@kai.com, kailand!pat),
Bart Schaefer (schaefer@cse.ogi.edu),
Nathan Glasser (nathan@brokaw.lcs.mit.edu),
Larry W. Virden (lvirden@cas.org),
Howard Chu (hyc@hanauma.jpl.nasa.gov),
Tim MacKenzie (tym@dibbler.cs.monash.edu.au),
Markku Jarvinen (mta@{cc,cs,ee}.tut.fi),
Marc Boucher (marc@CAM.ORG),
Doug Siebert (dsiebert@isca.uiowa.edu),
Ken Stillson (stillson@tsfsrv.mitre.org),
Ian Frechett (frechett@spot.Colorado.EDU),
Brian Koehmstedt (bpk@gnu.ai.mit.edu),
Don Smith (djs6015@ultb.isc.rit.edu),
Frank van der Linden (vdlinden@fwi.uva.nl),
Martin Schweikert (schweik@cpp.ob.open.de),
David Vrona (dave@sashimi.lcu.com),
E. Tye McQueen (tye%spillman.UUCP@uunet.uu.net),
Matthew Green (mrg@eterna.com.au),
Christopher Williams (cgw@pobox.com),
Matt Mosley (mattm@access.digex.net),
Gregory Neil Shapiro (gshapiro@wpi.WPI.EDU),
Johannes Zellner (johannes@zellner.org),
Pablo Averbuj (pablo@averbuj.com).
VERSION
This is version 3.9.15. Its roots are a merge of a custom
version 2.3PR7 by Wayne Davison and several enhancements
to Oliver Laumann's version 2.0. Note that all versions
numbered 2.x are copyright by Oliver Laumann.
AVAILABILITY
The latest official release of screen available via anony-
mous ftp from gnudist.gnu.org, nic.funet.fi or any other
GNU distribution site. The home site of screen is ftp.uni-
erlangen.de, in the directory pub/utilities/screen. The
subdirectory `private' contains the latest beta testing
release. If you want to help, send a note to screen@uni-
erlangen.de.
BUGS
o `dm' (delete mode) and `xs' are not handled correctly
(they are ignored). `xn' is treated as a magic-margin
indicator.
o Screen has no clue about double-high or double-wide
characters. But this is the only area where vttest is
allowed to fail.
o It is not possible to change the environment variable
$TERMCAP when reattaching under a different terminal
type.
o The support of terminfo based systems is very limited.
Adding extra capabilities to $TERMCAP may not have any
effects.
o Screen does not make use of hardware tabs.
o Screen must be installed as set-uid with owner root on
most systems in order to be able to correctly change
the owner of the tty device file for each window. Spe-
cial permission may also be required to write the file
"/etc/utmp".
o Entries in "/etc/utmp" are not removed when screen is
killed with SIGKILL. This will cause some programs
(like "w" or "rwho") to advertise that a user is logged
on who really isn't.
o Screen may give a strange warning when your tty has no
utmp entry.
o When the modem line was hung up, screen may not auto-
matically detach (or quit) unless the device driver is
configured to send a HANGUP signal. To detach a screen
session use the -D or -d command line option.
o If a password is set, the command line options -d and
-D still detach a session without asking.
o Both "breaktype" and "defbreaktype" change the break
generating method used by all terminal devices. The
first should change a window specific setting, where
the latter should change only the default for new win-
dows.
o When attaching to a multiuser session, the user's
.screenrc file is not sourced. Each user's personal
settings have to be included in the .screenrc file from
which the session is booted, or have to be changed man-
ually.
o A weird imagination is most useful to gain full advan-
tage of all the features.
o Send bug-reports, fixes, enhancements, t-shirts, money,
beer & pizza to screen@uni-erlangen.de.
Mar 2003 SCREEN(1)
