TclX(3Tcl)TclX(3Tcl)NAME
TclX - Extended Tcl: Extended command set for Tcl
INTRODUCTION
This man page contains the documentation for all of the extensions that
are added to Tcl 7.4 by Extended Tcl (TclX 7.4a). These extensions
increase Tcl's capabilities by adding new commands to it, without
changing the syntax of standard Tcl. Extended Tcl is a superset of
standard Tcl and is built alongside the standard Tcl sources. Extended
Tcl has three basic functional areas: A set of new commands, a Tcl shell
(i.e. a Unix shell-style command line and interactive environment), and
a user-extensible library of useful Tcl procedures, any of which can be
automatically loaded on the first attempt to execute it.
The command descriptions are separated into several sections:
o General Commands
o Debugging and Development Commands
o Unix Access Commands
o File Commands
o TCP/IP Server Access
o File Scanning Commands
o Math Commands
o List Maninipulation Commands
o Keyed Lists
o String and Character Manipulation Commands
o XPG/3 Message Catalog Commands
o Extended Tcl Shell
o Help Facility
o Tcl Loadable Libraries and Packages
GENERAL COMMANDS
A set of general, useful Tcl commands, includes a command to begin an
interactive session with Tcl, a facility for tracing execution, and a
looping command.
dirs This procedure lists the directories in the directory stack.
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commandloop ?prompt1? ?prompt2?
Create an interactive command loop for the current TCL interpreter.
This command receives commands from stdin and executes them. It is
useful TCL scripts that do not normally converse interactively with
a user through a Tcl command interpreter, but which sometimes want
to enter this mode.
Prompt1 is a Tcl command that is evaluated to output a prompt
string. The old value of tcl_prompt1 is saved and it is set to this
value for the duration of the command loop. Prompt2 is a command
that is evaluated to output the ``downlevel prompt'', which is the
prompt which is issued for continuation input. The old value of
tcl_prompt2 is saved and it is set to this value for the duration of
the command loop.
When the command terminates, the variables for the prompt hooks will
be set to their old value. If these arguments are not specified,
the prompt hooks use their current value.
echo ?str ...?
Writes zero or more strings to standard output, followed by a
newline.
infox option
Return information about Extended Tcl, or the current application.
The following infox command options are available:
version
Return the version number of Extended Tcl. The version number
for Extended Tcl is generated by combining the base version of
the standard Tcl code with a letter indicating the version of
Extended Tcl being used. This is the documentation for version
7.4a.
patchlevel
Return the patchlevel for Extended Tcl.
have_fchown
Return 1 if the fchown system call is available. This supports
the -fileid option on the chown and chgrp commands.
have_fchmod
Return 1 if the fchmod system call is available. This supports
the -fileid option on the chmod command.
have_flock
Return 1 if the flock command defined, 0 if it is not
available.
have_fsync
Return 1 if the fsync system call is available and the sync
command will sync individual files. 0 if it is not available
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and the sync command will always sync all file buffers.
have_ftruncate
Return 1 if the ftruncate system call is available. If it is,
the ftruncate command -fileid option maybe used.
have_msgcats
Return 1 if XPG message catalogs are available, 0 if they are
not. The catgets is designed to continue to function without
message catalogs, always returning the default string.
have_posix_signals
Return 1 if Posix signals are available (block and unblock
options available for the signal command). 0 is returned if
Posix signals are not available.
have_sockets
Return 1 if sockets are available (server_* suite and fstat
localhost and remotehost options). 0 is returned if sockets
are not available.
have_truncate
Return 1 if the truncate of chsize system call is available.
If it is, the ftruncate command will work.
appname
Return the symbolic application name of the current application
linked with the Extended Tcl library. The C variable
tclAppName must be set by the application to return an
application specific value for this variable.
applongname
Return a natural language name for the current application. The
C variable tclLongAppName must be set by the application to
return an application specific value for this variable.
appversion
Return the version number for the current application. The C
variable tclAppVersion must be set by the application to return
an application-specific value for this variable.
apppatchlevel
Return the patchlevel for the current application. The C
variable tclAppPatchlevel must be set by the application to
return an application-specific value for this variable.
for_array_keys var array_name code
This procedure performs a foreach-style loop for each key in the
named array. The break and continue statements work as with
foreach.
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for_recursive_glob var dirlist globlist code
This procedure performs a foreach-style loop over recursively
matched files. All directories in dirlist are recursively searched
(breadth-first), comparing each file found against the file glob
patterns in globlist. For each matched file, the variable var is
set to the file path and code is evaluated. Symbolic links are not
followed.
loop var first limit ?increment? body
Loop is a looping command, similar in behavior to the Tcl for
statement, except that the loop statement achieves substantially
higher performance and is easier to code when the beginning and
ending values of a loop are known, and the loop variable is to be
incremented by a known, fixed amount every time through the loop.
The var argument is the name of a Tcl variable that will contain
the loop index. The loop index is set to the value specified by
first. The Tcl interpreter is invoked upon body zero or more times,
where var is incremented by increment every time through the loop,
or by one if increment is not specified. Increment can be negative
in which case the loop will count downwards.
When var reaches limit, the loop terminates without a subsequent
execution of body. For instance, if the original loop parameters
would cause loop to terminate, say first was one, limit was zero and
increment was not specified or was non-negative, body is not
executed at all and loop returns.
The first, limit and increment are integer expressions. They are
only evaulated once at the beginning of the loop.
If a continue command is invoked within body then any remaining
commands in the current execution of body are skipped, as in the for
command. If a break command is invoked within body then the loop
command will return immediately. Loop returns an empty string.
popd
This procedure pops the top directory entry from the directory stack
and make it the current directory.
pushd ?dir?
This procedure pushs the current directory onto the directory stack
and cd to the specified directory. If the directory is not
specified, then the current directory is pushed, but remains
unchanged.
recursive_glob dirlist globlist
This procedure returns a list of recursively matches files. All
directories in dirlist are recursively searched (breadth-first),
comparing each file found against the file glob patterns in
globlist. Symbolic links are not followed.
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showproc ?procname ...?
This procedure lists the definition of the named procedures.
Loading them if it is not already loaded. If no procedure names are
supplied, the definitions of all currently loaded procedures are
returned.
This section contains information on commands and procdures that are
useful for developing and debugging Tcl scripts.
cmdtrace level|on ?noeval? ?notruncate? ?procs? ?fileid?
Print a trace statement for all commands executed at depth of level
or below (1 is the top level). If on is specified, all commands at
any level are traced. The following options are available:
noeval
Causes arguments to be printed unevaluated. If noeval is
specified, the arguments are printed before evaluation.
Otherwise, they are printed afterwards.
If the command line is longer than 60 characters, it is
truncated to 60 and a "..." is postpended to indicate that
there was more output than was displayed. If an evaluated
argument contains a space, the entire argument will be enclosed
inside of braces (`{}') to allow the reader to visually
separate the arguments from each other.
notruncate
Disables the truncation of commands and evaluated arguments.
procs
Enables the tracing of procedure calls only. Commands that
aren't procedure calls (i.e. calls to commands that are written
in C, C++ or some object-compatible language) are not traced if
the procs option is specified. This option is particularly
useful for greatly reducing the output of cmdtrace while
debugging.
fileid
This is a file id as returned by the open command. If
specified, then the trace output will be written to the file
rather than stdout. A stdio buffer flush is done after every
line is written so that the trace may be monitored externally
or provide useful information for debugging problems that cause
core dumps.
The most common use of this command is to enable tracing to a file during
the development. If a failure occurs, a trace is then available when
needed. Command tracing will slow down the execution of code, so it
should be removed when code is debugged. The following command will
enable tracing to a file for the remainder of the program:
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cmdtrace on [open cmd.log w]
cmdtrace off
Turn off all tracing.
cmdtrace depth
Returns the current maximum trace level, or zero if trace is
disabled.
edprocs ?proc...?
This procedure writes the named procedures, or all currently defined
procedures, to a temporary file, then calls an editor on it (as
specified by the EDITOR environment variable, or vi if none is
specified), then sources the file back in if it was changed.
profile ?-commands? on
profile off arrayVar
This command is used to collect a performance profile of a Tcl
script. It collects data at the Tcl procedure level. The number of
calls to a procedure, and the amount of real and CPU time is
collected. Time is also collected for the global context. The
procedure data is collected by bucketing it based on the procedure
call stack, this allows determination of how much time is spent in a
particular procedure in each of it's calling contexts.
The on option enables profile data collection. If the -commands
option is specifed, data on all commands within a procedure is
collected as well a procedures. Multiple occurrences of a command
within a procedure are not distinguished, but this data may still be
useful for analysis.
The off option turns off profiling and moves the data collected to
the array arrayVar. The array is address by a list containing the
procedure call stack. Element zero is the top of the stack, the
procedure that the data is for. The data in each entry is a list
consisting of the procedure call count and the real time and CPU
time in milliseconds spent in the procedure (and all procedures it
called). The list is in the form {count real cpu}. A Tcl procedure
profrep is supplied for reducing the data and producing a report
profrep profDataVar sortKey ?outFile? ?userTitle?
This procedure generates a report from data collect from the profile
command. ProfDataVar is the name of the array containing the data
returned by the profile command. SortKey indicates which data value
to sort by. It should be one of "calls", "cpu" or "real". OutFile
is the name of file to write the report to. If omitted, stdout is
assumed. UserTitle is an optional title line to add to output.
saveprocs fileName ?proc...?
This prodcure saves the definition of the named procedure, or all
currently defined procedures if none is specified, to the named
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file.
UNIX ACCESS COMMANDS
These commands provide access to many basic Unix facilities, including
process handling, date and time processing, signal handling and the
executing commands via the shell.
alarm seconds
Instructs the system to send a SIGALRM signal in the specified
number of seconds. This is a floating point number, so fractions of
a section may be specified. If seconds is 0.0, any previous alarm
request is canceled. Only one alarm at a time may be active; the
command returns the number of seconds left in the previous alarm.
On systems without the setitimer system call, seconds is rounded up
to an integer number of seconds.
convertclock dateString ?GMT|{}? ?baseClock?
Convert dateString to an integer clock value (see getclock). This
command can parse and convert virtually any standard date and/or
time string, which can include standard time zone mnemonics. If
only a time is specified, the current date is assumed. If the
string does not contain a time zone mnemonic, the local time zone is
assumed, unless the GMT argument is specified, in which case the
clock value is calculated assuming that the specified time is
relative to Greenwich Mean Time.
If baseClock is specified, it should contain an integer clock value.
Only the date in this value is used, not the time. This is useful
for determining the time on a specific day or doing other date-
relative conversions.
The character string consists of zero or more specifications of the
following form:
time - A time of day, which is of the form hh[:mm[:ss]] [meridian]
[zone] or hhmm [meridian] [zone]. If no meridian is specified, hh
is interpreted on a 24-hour clock.
date - A specific month and day with optional year. The acceptable
formats are mm/dd[/yy], monthname dd[, yy], dd monthname [yy], and
day, dd monthname yy. The default year is the current year. If the
year is less then 100, then 1900 is added to it.
relative time - A specification relative to the current time. The
format is number unit; acceptable units are year, fortnight, month,
week, day, hour, minute (or min), and second (or sec). The unit can
be specified as a singular or plural, as in 3 weeks. These
modifiers may also be specified: tomorrow, yesterday, today, now,
last, this, next, ago.
The actual date is calculated according to the following steps.
First, any absolute date and/or time is processed and converted.
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Using that time as the base, day-of-week specifications are added.
Next, relative specifications are used. If a date or day is
specified, and no absolute or relative time is given, midnight is
used. Finally, a correction is applied so that the correct hour of
the day is produced after allowing for daylight savings time
differences.
convertclock ignores case when parsing all words. The names of the
months and days of the week can be abbreviated to their first three
letters, with optional trailing period. Periods are ignored in any
timezone or meridian values.
Note that convertclock will convert symbolic time-zone names, but
these are not standardized and there are conflicts with various
parts of the world. Use GMT when trying to produce a portable time
that can then be converted back to a numeric value.
The only dates in the range 1902 and 2037 may be converted. Some
examples are:
convertclock "14 Feb 92"
convertclock "Feb 14, 1992 12:20 PM PST"
convertclock "12:20 PM Feb 14, 1992"
execl ?-argv0 argv0? prog ?arglist?
Do an execl, replacing the current program (either Extended Tcl or
an application with Extended Tcl embedded into it) with prog and
passing the arguments in the list arglist.
The -argv0 options specifies that argv0 is to be passed to the
program as argv [0] rather than prog.
Note: If you are using execl in a Tk application and it fails, you
may not do anything that accesses the X server or you will receive a
BadWindow error from the X server. This includes executing the Tk
version of the exit command. We suggest using the following command
to abort Tk applications after an execl failure:
kill [id process]
fmtclock clockval ?format? ?GMT|{}?
Converts a Unix integer time value, typically returned by getclock,
convertclock, or the atime, mtime, or ctime options of the file
command, to human-readable form. The format argument is a string
that describes how the date and time are to be formatted. Field
descriptors consist of a ``%'' followed by a field descriptor
character. All other characters are copied into the result. Valid
field descriptors are:
%% - Insert a %.
%a - Abbreviated weekday name.
%A - Full weekday name
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%b - Abbreviated month name.
%B - Full month name.
%d - Day of month (01 - 31).
%D - Date as %m/%d/%y.
%e - Day of month (1-31), no leading zeros.
%h - Abbreviated month name.
%H - Hour (00 - 23).
%I - Hour (00 - 12).
%j - Day number of year (001 - 366).
%m - Month number (01 - 12).
%M - Minute (00 - 59).
%n - Insert a new line.
%p - AM or PM.
%r - Time as %I:%M:%S %p.
%R - Time as %H:%M.
%S - Seconds (00 - 59).
%t - Insert a tab.
%T - Time as %H:%M:%S.
%U - Week number of year (01 - 52), Sunday is the first
day of the week.
%w - Weekday number (Sunday = 0).
%W - Week number of year (01 - 52), Monday is the first
day of the week.
%x - Local specific date format.
%X - Local specific time format.
%y - Year within century (00 - 99).
%Y - Year as ccyy (e.g. 1990)
%Z - Time zone name.
If format is not specified, "%a %b %d %H:%M:%S %Z %Y" is used. If
GMT is specified, the time will be formated as Greenwich Mean Time.
If the argument is not specified or is empty, then the local
timezone will be used as defined by the operating environment.
chroot dirname
Change root directory to dirname, by invoking the POSIX chroot(2)
system call. This command only succeeds if running as root.
fork
Fork the current Tcl process. Fork returns zero to the child
process and the process number of the child to the parent process.
If the fork fails, a Tcl error is generated.
If an execl is not going to be performed before the child process
does output, or if a close and dup sequence is going to be performed
on stdout or stderr, then a flush should be issued against stdout,
stderr and any other open output file before doing the fork.
Otherwise characters from the parent process pending in the buffers
will be output by both the parent and child processes.
Note: If you are forking in a Tk based apllication you must execl
before doing any window operations in the child or you will receive
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a BadWindow error from the X server.
getclock
Return the current date and time as a system-dependent integer
value. The unit of the value is seconds, allowing it to be used for
relative time calculations.
id options
This command provides a means of getting, setting and converting
user, group and process ids. The id command has the following
options:
id user ?name?
id userid ?uid?
Set the real and effective user ID to name or uid, if the name
(or uid) is valid and permissions allow it. If the name (or
uid) is not specified, the current name (or uid) is returned.
id convert userid uid
id convert user name
Convert a user ID number to a user name, or vice versa.
id group ?name?
id groupid ?gid?
Set the real and effective group ID to name or gid, if the name
(or gid) is valid and permissions allow it. If the group name
(or gid) is not specified, the current group name (or gid) is
returned.
id groups
id groupids
Return the current group access list of the process. The
option groups returns group names and groupids returns id
numbers.
id convert groupid gid
id convert group name
Convert a group ID number to a group name, or vice versa.
id effective user
id effective userid
Return the effective user name, or effective user ID number,
respectively.
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id effective group
id effective groupid
Return the effective group name, or effective group ID number,
respectively.
id effective groupids
Return all of the groupids the user is a member of.
id host
Return the hostname of the system the program is running on.
id process
Return the process ID of the current process.
id process parent
Return the process ID of the parent of the current process.
id process group
Return the process group ID of the current process.
id process group set
Set the process group ID of the current process to its process
ID.
id host
Returns the standard host name of the machine the process is
executing on.
kill ?-pgroup? ?signal? idlist
Send a signal to the each process in the list idlist, if permitted.
Signal, if present, is the signal number or the symbolic name of the
signal, see the signal system call manual page. The leading ``SIG''
is optional when the signal is specified by its symbolic name. The
default for signo is 15, SIGTERM.
If -pgroup is specified, the numbers in idlist are take as process
group ids and the signal is sent to all of the process in that
process group. A process group id of 0 specifies the current
process group.
link ?-sym? srcpath destpath
Create a directory entry, destpath, linking it to the existing file,
srcpath. If -sym is specified, a symbolic link, rather than a hard
link, is created. (The -sym option is only available on systems
that support symbolic links.)
mkdir ?-path? dirList
Create each of the directories in the list dirList. The mode on the
new directories is 777, modified by the umask. If -path is
specified, then any non-existent parent directories in the specified
path(s) are also created.
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nice ?priorityincr?
Change or return the process priority. If priorityincr is omitted,
the current priority is returned. If priorityincr is positive, it
is added to the current priority level, up to a system defined
maximum (normally 19),
Negative priorityincr values cumulatively increase the program's
priority down to a system defined minimum (normally -19); increasing
priority with negative niceness values will only work for the
superuser.
The new priority is returned.
readdir dirPath
Returns a list containing the contents of the directory dirPath.
The directory entries "." and ".." are not returned.
rmdir ?-nocomplain? dirList
Remove each of the directories in the list dirList. If -nocomplain
is specified, then errors will be ignored.
signal action siglist ?command?
Specify the action to take when a Unix signal is received by
Extended Tcl, or a program that embeds it. Siglist is a list of
either the symbolic or numeric Unix signal (the SIG prefix is
optional). Action is one of the following actions to be performed
on receipt of the signal. To specify all modifiable signals, use
`*' (this will not include SIGKILL and SIGSTOP, as they can not be
modified).
default - Perform system default action when signal is received (see
signal system call documentation).
ignore - Ignore the signal.
error - Generate a catchable Tcl error. It will be as if the
command that was running returned an error. The error code will be
in the form:
POSIX SIG signame
For the death of child signal, signame will always be SIGCHLD,
rather than SIGCLD, to allow writing portable code.
trap - When the signal occurs, execute command and continue
execution if an error is not returned by command. The command will
be executed in the global context. The command will be edited
before execution, replacing occurrences of "%S" with the signal
name. Occurrences of "%%" result in a single "%". This editing
occurs just before the trap command is evaluated. If an error is
returned, then follow the standard Tcl error mechanism. Often
command will just do an exit.
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get - Retrieve the current settings of the specified signals. A
keyed list will be returned were the keys are one of the specified
signals and the values are a list cosisting of the action associated
with the signal, a 0 if the signal may be delivered (not block) and
a 1 if it is blocked. The actions maybe one of `default',`ignore',
`error' or `trap. If the action is trap, the third element is the
command associated with the action. The action `unknown' is
returned if a non-Tcl signal handler has been associated with the
signal.
set - Set signals from a keyed list in the format returned by the
get. For this action, siglist is the keyed list of signal state.
Signals with an action of `unknown' are not modified.
block - Block the specified signals from being received. (Posix
systems only).
unblock - Allow the specified signal to be received. Pending signals
will not occur. (Posix systems only).
The signal action will remain enabled after the specified signal has
occurred. The exception to this is SIGCHLD on systems without Posix
signals. For these systems, SIGCHLD is not be automatically
reenabled. After a SIGCHLD signal is received, a call to wait must
be performed to retrieve the exit status of the child process before
issuing another signal SIGCHLD ... command. For code that is to be
portable between both types of systems, use this approach.
Signals are not processed until after the completion of the Tcl
command that is executing when the signal is received. If an
interactive Tcl shell is running, then the SIGINT will be set to
error, non-interactive Tcl sessions leave SIGINT unchanged from when
the process started (normally default for foreground processes and
ignore for processes in the background).
sleep seconds
Sleep the Extended Tcl process for seconds seconds.
system command
Executes command via the system(3) call. Differs from exec in that
system doesn't return the executed command's standard output as the
result string, and system goes through the Unix shell to provide
wildcard expansion, redirection, etc, as is normal from an sh
command line. The exit code of the command is returned.
sync ?fileId?
If fileId is not specified, or if it is and this system does not
support the fsync system call, issues a sync system call to flush
all pending disk output. If fileId is specified and the system does
support the fsync system call, issues an fsync on the file
corresponding to the specified Tcl fileId to force all pending
output to that file out to the disk.
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If fileId is specified, the file must be writable. A flush will be
issued against the fileId before the sync.
The infox have_fsync command can be used to determine if "sync
fileId" will do a sync or a fsync.
times
Return a list containing the process and child execution times in
the form:
utime stime cutime cstime
Also see the times(2) system call manual page. The values are in
milliseconds.
umask ?octalmask?
Sets file-creation mode mask to the octal value of octalmask. If
octalmask is omitted, the current mask is returned.
unlink ?-nocomplain? filelist
Delete (unlink) the files whose names are in the list filelist. If
-nocomplain is specified, then errors will be ignored.
wait ?-nohang? ?-untraced? ?-pgroup? ?pid?
Waits for a process created with the execl command to terminate,
either due to an untrapped signal or call to exit system call. If
the process id pid is specified, they wait on that process,
otherwise wait on any child process to terminate.
If -nohang is specified, then don't block waiting on a process to
terminate. If no process is immediately available, return an empty
list. If -untraced is specified then the status of child processes
that are stopped, and whose status has not yet been reported since
they stopped, are also returned. If -pgroup is specfied and pid is
not specified, then wait on any child process whose process groupd
ID is they same as the calling process. If pid is specified with
-pgroup, then it is take as a process group ID, waiting on any
process in that process group to terminate.
Wait returns a list containing three elements: The first element is
the process id of the process that terminated. If the process
exited normally, the second element is `EXIT', and the third
contains the numeric exit code. If the process terminated due to a
signal, the second element is `SIG', and the third contains the
signal name. If the process is currently stopped (on systems that
support SIGSTP), the second element is `STOP', followed by the
signal name.
Note that it is possible to wait on processes to terminate that were
create in the background with the exec command. However, if any
other exec command is executed after the process terminates, then
the process status will be reaped by the exec command and will not
be available to the wait command.
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TclX(3Tcl)TclX(3Tcl)FILE COMMANDS
These commands provide extended file access and manipulation. This
includes searching ASCII-sorted data files, copying files, duplicating
file descriptors, control of file access options, retrieving open file
status, and creating pipes with the pipe system call. Also linking and
unlinking files, setting file, process, and user attributes and
truncating files. An interface to the select system call is available on
Unix systems that support it.
It should be noted that Tcl file I/O is implemented on top of the stdio
library. By default, the file is buffered. When communicating to a
process through a pipe, a flush command should be issued to force the
data out. Alternatively, the fcntl command may be used to set the
buffering mode of a file to line-buffered or unbuffered.
bsearch fileId key ?retvar? ?compare_proc?
Search an opened file fileId containing lines of text sorted into
ascending order for a match. Key contains the string to match. If
retvar is specified, then the line from the file is returned in
retvar, and the command returns 1 if key was found, and 0 if it
wasn't. If retvar is not specified or is a null name, then the
command returns the line that was found, or an empty string if key
wasn't found.
By default, the key is matched against the first white-space
separated field in each line. The field is treated as an ASCII
string. If compare_proc is specified, then it defines the name of a
Tcl procedure to evaluate against each line read from the sorted
file during the execution of the bsearch command. Compare_proc
takes two arguments, the key and a line extracted from the file.
The compare routine should return a number less than zero if the key
is less than the line, zero if the key matches the line, or greater
than zero if the key is greater than the line. The file must be
sorted in ascending order according to the same criteria
compare_proc uses to compare the key with the line, or errouenous
results will occur.
copyfile ?-bytes num|-maxbytes num? fromFileId toFileId
Copies the rest of the file specified by fromFileId, starting from
its current position, to the file specified by toFileId, starting
from its current position.
If -bytes is specified, then num bytes are copied. If less than num
bytes are available, an error is returned. If -maxbytes is
specified, then num bytes are copied but no error is returned if
less are available.
The command returns the number of bytes that were copied.
The -bytes option is particularly useful for mixing binary data in
with ASCII commands or data in a data stream.
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chmod [-fileid] mode filelist
Set permissions of each of the files in the list filelist to mode,
where mode is an absolute numeric mode or symbolic permissions as in
the UNIX chmod(1) command. To specify a mode as octal, it should be
prefixed with a "0" (e.g. 0622).
If the option -fileid is specified, filelist is a list of open file
identifiers rather than a list of file names. This option is not
available on all Unix systems. Use the infox have_fchmod command to
determine if this functionallity is available.
chown [-fileid] owner|{owner group} filelist
Set owner of each file in the list filelist to owner, which can be a
user name or numeric user id. If the first parameter is a list,
then the owner is set to the first element of the list and the group
is set to the second element. Group can be a group name or numeric
group id. If group is {}, then the file group will be set to the
login group of the specified user.
If the option -fileid is specified, filelist is a list of open file
identifiers rather than a list of file names. This option is not
available on all Unix systems. Use the infox have_fchown command to
determine if this functionallity is available.
chgrp [-fileid] group filelist
Set the group id of each file in the list filelist to group, which
can be either a group name or a numeric group id.
If the option -fileid is specified, filelist is a list of open file
identifiers rather than a list of file names. This option is not
available on all Unix systems. Use the infox have_fchown command to
determine if this functionallity is available.
dup fileId ?targetFileId?
Duplicate an open file. A new file id is opened that addresses the
same file as fileId.
If targetFileId is specified, the the file is dup to this specified
file id. Normally this is stdin, stdout, or stderr. The dup
command will handle flushing output and closing this file. The new
file will be buffered, if its needs to be unbuffered, use the fcntl
command to set it unbuffered.
If fileId is a number rather than a Tcl file id, then the dup
command will bind that file to a Tcl file id. This is usedful for
accessing files that are passed from the parent process. The
argument ?targetFileId? is not valid with this operation.
fcntl fileId attribute ?value?
This command either sets or clears a file option or returns its
current value. If value are not specified, then the current value
of attribute is returned. The following attributes may be specified:
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RDONLY - The file is opened for reading only. (Get only)
WRONLY - The file is opened for writing only. (Get only)
RDWR - The file is opened for reading and writing. (Get only)
READ - If the file is readable. (Get only).
WRITE - If the file is writable. (Get only).
APPEND - The file is opened for append-only writes. All writes will
be forced to the end of the file.
NONBLOCK - The file is to be accessed with non-blocking I/O. See
the read system call for a description of how it affects the
behavior of file reads.
CLOEXEC - Close the file on an process exec. If the execl command
or some other mechanism causes the process to do an exec, the file
will be closed if this option is set.
NOBUF - The file is not buffered. If set, then there no stdio
buffering for the file.
LINEBUF - Output the file will be line buffered. The buffer will be
flushed when a newline is written, when the buffer is full, or when
input is requested.
The APPEND, NONBLOCK, and CLOEXEC attributes may be set or cleared
by specifying the attribute name and a value 1 to set the attribute
and 0 to clear it.
The NOBUF and LINEBUF attributes may only be set (a value of 1) and
only one of the options may be selected. Once set, it may not be
changed. These options should be set before any I/O operations have
been done on the file or data may be lost.
flock options fileId ?start? ?length? ?origin?
This command places a lock on all or part of the file specified by
fileId. The lock is either advisory or mandatory, depending on the
mode bits of the file. The lock is placed beginning at relative
byte offset start for length bytes. If start or length is omitted
or empty, zero is assumed. If length is zero, then the lock always
extents to end of file, even if the file grows. If origin is
"start", then the offset is relative to the beginning of the file.
If it is "current", it is relative to the current access position in
the file. If it is "end", then it is relative to the end-of-file (a
negative is before the EOF, positive is after). If origin is
omitted, start is assumed.
The following options are recognized:
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TclX(3Tcl)TclX(3Tcl)-read - Place a read lock on the file. Multiple processes may be
accessing the file with read-locks.
-write - Place a write lock on the file. Only one process may be
accessing a file if there is a write lock.
-nowait - If specified, then the process will not block if the lock
can not be obtained. With this option, the command returns 1 if the
lock is obtained and 0 if it is not.
See your system's fcntl system call documentation for full details
of the behavior of file locking. If locking is being done on ranges
of a file, it is best to use unbuffered file access (see the fcntl
command).
for_file var filename { code }
This procedure implements a loop over the contents of a file. For
each line in filename, it sets var to the line and executes code.
The break and continue commands work as with foreach.
For example, the command
for_file line /etc/passwd {echo $line}
would echo all the lines in the password file.
funlock fileId ?start? ?length? ?origin?
Remove a locked from a file that was previously placed with the
flock command. The arguments are the same as for the flock command,
see that command for more details.
fstat fileId ?item?|?stat arrayvar?
Obtain status information about an open file.
The following keys are used to identify data items:
o atime - The time of last access.
o ctime - The time of last file status change
o dev - The device containing a directory for the file. This value
uniquely identifies the file system that contains the file.
o gid - The group ID of the file's group.
o ino - The inode number. This field uniquely identifies the file
in a given file system.
o mode - The mode of the file (see the mknod system call).
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o mtime - Time when the data in the file was last modified.
o nlink - The number of links to the file.
o size - The file size in bytes.
o tty - If the file is associated with a terminal, then 1 otherwise
0.
o type - The type of the file in symbolic form, which is one of the
following values: file, directory, characterSpecial, blockSpecial,
fifo, link, or socket.
o uid - The user ID of the file's owner.
If one of these keys is specified as item, then that data item is
returned.
If stat arrayvar is specified, then the information is returned in
the array arrrayvar. Each of the above keys indexes an element of
the array containing the data.
If only fileId is specified, the command returns the data as a keyed
list.
The following values may be returned only if explicitly asked for,
it will not be returned with the array or keyed list forms:
o remotehost - If fileId is a TCP/IP socket connection, then a list
is returned with the first element being the remote host IP address.
If the remote host name can be found, it is returned as the second
element of the list. The remote host IP port number is returned as
the this element.
o localhost - If fileId is a TCP/IP socket connection, then a list
is returned with the first element being the local host IP address.
If the local host name can be found, it is returned as the second
element of the list. The local host IP port number is returned as
the this element.
ftruncate [-fileid] file newsize
Truncate a file to have a length of at most newsize bytes.
If the option -fileid is specified, file is an open file identifier,
otherwise it is a file path.
This command is not available on all systems if the underlying
operating system support is not available. The command infox
have_truncate will indicate if this command is available. On some
systems, the -fileid option is not available, check the result of
infox have_ftruncate to see if it can be used.
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lgets fileId ?varName?
Reads the next Tcl list from the file given by fileId and discards
the terminating newline character. This command differs from the
gets command, in that it reads Tcl lists rather than lines. If the
list contains a newline, then that newline will be returned as part
of the result. Only a newline not quoted as part of the list
indicates the end of the list. There is no corresponding command
for outputing lists, as puts will do this correctly. If varName is
specified, then the line is placed in the variable by that name and
the return value is a count of the number of characters read (not
including the newline). If the end of the file is reached before
reading any characters then -1 is returned and varName is set to an
empty string. If varName is not specified then the return value
will be the line (minus the newline character) or an empty string if
the end of the file is reached before reading any characters. An
empty string will also be returned if a line contains no characters
except the newline, so eof may have to be used to determine what
really happened.
frename oldPath newPath
Renames oldPath to newPath. This command does not support renaming
across file systems.
pipe ?fileId_var_r fileId_var_w?
Create a pipe. If fileId_var_r and fileId_var_r are specified, then
pipe will set the a variable named fileId_var_r to contain the
fileId of the side of the pipe that was opened for reading, and
fileId_var_w will contain the fileId of the side of the pipe that
was opened for writing.
If the fileId variables are not specified, then a list containing
the read and write fileIdw is returned as the result of the command.
read_file ?-nonewline? fileName
read_file fileName numBytes
This proecure reads the file fileName and returns the contents as a
string. If -nonewline is specified, then the last character of the
file is discarded if it is a newline. The second form specifies
exactly how many bytes will be read and returned, unless there are
fewer than numBytes bytes left in the file; in this case, all the
remaining bytes are returned.
select readfileIds ?writefileIds? ?exceptfileIds? ?timeout?
This command allows an Extended Tcl program to wait on zero or more
files being ready for for reading, writing, have an exceptional
condition pending, or for a timeout period to expire. readFileIds,
writeFileIds, exceptFileIds are each lists of fileIds, as returned
from open, to query. An empty list ({}) may be specified if a
category is not used.
The files specified by the readFileIds list are checked to see if
data is available for reading. The writeFileIds are checked if the
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specified files are clear for writing. The exceptFileIds are
checked to see if an exceptional condition has occured (typically,
an error). The write and exception checking is most useful on
devices, however, the read checking is very useful when
communicating with multiple processes through pipes. Select
considers data pending in the stdio input buffer for read files as
being ready for reading, the files do. not have to be unbuffered.
Timeout is a floating point timeout value, in seconds. If an empty
list is supplied (or the parameter is omitted), then no timeout is
set. If the value is zero, then the select command functions as a
poll of the files, returning immediately even if none are ready.
If the timeout period expires with none of the files becomming
ready, then the command returns an empty list. Otherwise the
command returns a list of three elements, each of those elements is
a list of the fileIds that are ready in the read, write and
exception classes. If none are ready in a class, then that element
will be the null list. For example:
select {file3 file4 file5} {file6 file7} {} 10.5
could return
{file3 file4} {file6} {}
or perhaps
file3 {} {}
write_file fileName string ?string...?
This procedure writes the specified strings to the named file.
TCP/IP SERVER ACCESS
Commands are provided to access TCP/IP-based servers, and to create them.
It is easy to build servers using Extended Tcl that run under inetd, or
even servers that run standalone and accept and manage multiple
simultaneous connections. The socket file handles maybe be read using
the either the gets or read command and written using either the puts or
server_send command.
The fstat remotehost and fstat localhost requests are useful both for
clients and servers. To obtain the host name of the system the script is
running on, use id host.
If a TclX script is setup to run under inetd, it is launched with its
stdin, stdout and stderr associated with the client socket. The standard
Tcl file ids stdin, stdout and stderr maybe then be used to communicate
with the client.
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server_connect ?options? host service
Open a TCP/IP connection to a server of host on the port specified
by service. The server is then accessed using the standard Tcl file
I/O commands. Host may be a host name or an IP address. Port may
be a port number of a service name.
If a destination host name is supplied and more that one address is
valid for the host, the host's addresses will be tried in the order
returned until one can be connected to, or the list is exhausted.
You may also use the server_info command to obtain the list of valid
address.
The options are:
o -buf - Specifies that the file is buffered. When writing to the
file, the flush command must be used to force data in the buffer to
be sent to the server. Buffered access will result in significantly
better performance when reading data, and will also improve the
performance of a series of writes done without intervening reads.
The buffering is only used when accessing the file via the gets,
read, and puts commands. The server_send command does not use the
buffer.
o -nobuf - The file is unbuffered. A single file id, open for both
reading and writing, is returned.
o -twoids - Return a pair of file ids in a list. The first id is
open for read access, the second for write access. The close
command must be called against both file ids when you are done using
the socket and they maybe closed independently. This option is
primarily intended to implement compatibility procedures for
deprecated commands, however it maybe useful for code that needs to
independently manage the read and write ends of the socket.
o -myip ipNumber - Define the IP number for your side of the
connection. This is useful for multi-homed hosts (hosts with more
than one IP address). Note that only IP addresses corresponding to
network interfaces on your machine may be used. If -myip is not
specified, the operating system will assign the IP number for you.
o -myport portNumber - Define the port number for your side of the
connection. If the port number is already in use, an error will be
returned. If the port number is in the privileged range, the Tcl
program will have to be running as superuser, or an error will be
returned.
server_create ?options?
Creates a TCP/IP server socket on the local machine. A file handle
is returned upon successful creation. When a connection request is
made to the server, the file handle becomes read-ready. Connections
can be accepted using server_accept.
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The file handle can be detected as read-ready using select, by using
fcntl to make the handle nonblocking and then calling server_accept,
or by using the Tk fileevent command.
Options are:
o -myip ipNumber - Define the IP number for your side of the
connection. This is useful for multi-homed hosts (hosts with more
than one IP address). Note that only IP addresses corresponding to
network interfaces on your machine may be used. If -myip is not
specified, the operating system will assign the IP number for you.
o -myport portNumber - Define the port number for your side of the
connection. If the port number is already in use, an error will be
returned. If the port number is in the privileged range, the Tcl
program will have to be running as superuser, or an error will be
returned.
o -backlog count - Maximum length the queue of pending connections
may grow to. If a connection request arrives with the queue full,
the client may receive an error with an indication of ECONNREFUSED,
or, if the underlying protocol supports retransmission, the request
may be ignored so that retries may succeed. Note that on at least
some BSD-based systems the backlog is silently limited to 5,
regardless of the value specified. The default is 5.
server_accept ?options? fileid
Accept a TCP/IP connection to the server socket associated with
fileid. Options are -buf, -nobuf and -twoids. See the
server_connect command for a description of these options. A file
handle (or a pair of file handles when -twoids) is return.
server_info addresses host
server_info official_name host
server_info aliases host
Optain information about a TCP/IP server. The argument host can be
either a host name or an IP address.
The following subcommands are recognized:
o addresses - Return the list of IP addresses for host.
o official_name - Return official name for host.
o aliases - Return the list of aliases for host. (Note that these
are IP number aliases, not DNS CNAME aliases. See ifconfig(2).)
server_send ?options? fileid string
Send the specified string to the TCP/IP connection corresponding to
fileid. Theserver_send command is provide as an option to puts for
writing to a socket as it is better at detecting lost connections
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and other IP-related error conditions. File buffering is ignored
for server_send. There is no need to flush after a server_send. The
results of mixing server_send with puts without flushing the puts
output is indeterminate.
Options are:
o -nonewline - Don't append a newline character to the end of the
message. The default is to append a newline character.
o -dontroute - Requests that routing be bypassed and the direct
interface used (usually used only by diagnostic or routing programs)
o -outofband - Send out-of-band data on the socket.
FILE SCANNING COMMANDS
These commands provide a facility to scan files, matching lines of the
file against regular expressions and executing Tcl code on a match. With
this facility you can use Tcl to do the sort of file processing that is
traditionally done with awk. And since Tcl's approach is more
declarative, some of the scripts that can be rather difficult to write in
awk are simple to code in Tcl.
File scanning in Tcl centers around the concept of a scan context. A
scan context contains one or more match statements, which associate
regular expressions to scan for with Tcl code to be executed when the
expressions are matched.
scancontext ?option?
This command manages file scan contexts. A scan context is a
collection of regular expressions and commands to execute when that
regular expression matches a line of the file. A context may also
have a single default match, to be applied against lines that do not
match any of the regular expressions. Multiple scan contexts may be
defined and they may be reused on multiple files. A scan context is
identified by a context handle. The scancontext command takes the
following forms:
scancontext create
Create a new scan context. The scanmatch command is used to define
patterns in the context. A contexthandle is returned, which the Tcl
programmer uses to refer to the newly created scan context in calls
to the Tcl file scanning commands.
scancontext delete contexthandle
Delete the scan context identified by contexthandle, and free all of
the match statements and compiled regular expressions associated
with the specified context.
scancontext copyfile contexthandle ?filehandle?
Set or return the file handle that unmatched lines are copied to.
(See scanfile). If filehandle is omitted, the copy file handle is
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returned. If no copy file is associated with the context, {} is
returned. If a file handle is specified, it becomes the copy file
for this context. If filehandle is {}, then it removes any copy
file specification for the context.
scanfile ?-copyfile copyFileId? contexthandle fileId
Scan the file specified by fileId, starting from the current file
position. Check all patterns in the scan context specified by
contexthandle against it, executing the match commands corresponding
to patterns matched.
If the optional -copyfile argument is specified, the next argument
is a file ID to which all lines not matched by any pattern
(excluding the default pattern) are to be written. If the copy file
is specified with this flag, instead of using the scancontext
copyfile command, the file is disassociated from the scan context at
the end of the scan.
scanmatch ?-nocase? contexthandle ?regexp? commands
Specify Tcl commands, to be evaluated when regexp is matched by a
scanfile command. The match is added to the scan context specified
by contexthandle. Any number of match statements may be specified
for a give context. Regexp is a regular expression (see the regexp
command). If -nocase is specified as the first argument, the
pattern is matched regardless of alphabetic case.
If regexp is not specified, then a default match is specified for
the scan context. The default match will be executed when a line of
the file does not match any of the regular expressions in the
current scancontext.
The array matchInfo is available to the Tcl code that is executed
when an expression matches (or defaults). It contans information
about the file being scanned and where within it the expression was
matched.
matchInfo is local to the top level of the match command unless
declared global at that level by the Tcl global command. If it is
to be used as a global, it must be declared global before scanfile
is called (since scanfile sets the matchInfo before the match code
is executed, a subsequent global will override the local variable).
The following array entries are available:
matchInfo(line)
Contains the text of the line of the file that was matched.
matchInfo(offset)
The byte offset into the file of the first character of the
line that was matched.
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TclX(3Tcl)TclX(3Tcl)matchInfo(linenum)
The line number of the line that was matched. This is relative
to the first line scanned, which is usually, but not
necessarily, the first line of the file. The first line is
line number one.
matchInfo(context)
The context handle of the context that this scan is associated
with.
matchInfo(handle)
The file id (handle) of the file currently being scanned.
matchInfo(copyHandle)
The file id (handle) of the file specified by the -copyfile
option. The element does not exist if -copyfile was not
specified.
matchInfo(submatch0)
Will contain the characters matching the first parenthesized
subexpression. The second will be contained in submatch1, etc.
matchInfo(subindex0)
Will contain the a list of the starting and ending indices of
the string matching the first parenthesized subexpression. The
second will be contained in subindex1, etc.
All scanmatch patterns that match a line will be processed in the order
in which their specifications were added to the scan context. The
remainder of the scanmatch pattern-command pairs may be skipped for a
file line if a continue is executed by the Tcl code of a preceding,
matched pattern.
If a return is executed in the body of the match command, the scanfile
command currently in progress returns, with the value passed to return as
its return value.
MATH COMMANDS
Several extended math commands commands make many additional math
functions available in TclX. In addition, a set of procedures provide
command access to the math functions supported by the expr command.
The following procedures provide command interfaces to the expr math
functions. They take the same arguments as the expr functions and may
take expressions as arguments.
abs acos asin atan2
atan ceil cos cosh
double exp floor fmod
hypot int log10 log
pow round sin sinh
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sqrt tan tanh
max num1 num2 ?..numN?
expr max(num1, num2)
Returns the argument that has the highest numeric value. Each
argument may be any integer or floating point value.
This functionality is also available as a math function max in the
Tcl expr command.
min num1 num2 ?..numN?
expr min(num1, num2)
Returns the argument that has the lowest numeric value. Each
argument may be any integer or floating point value.
This functionality is also available as a math function min in the
Tcl expr command.
random limit | seed ?seedval?
Generate a pseudorandom integer number greater than or equal to zero
and less than limit. If seed is specified, then the command resets
the random number generator to a starting point derived from the
seedval. This allows one to reproduce pseudorandom number sequences
for testing purposes. If seedval is omitted, then the seed is set
to a value based on current system state and the current time,
providing a reasonably interesting and ever-changing seed.
LIST MANINIPULATION COMMANDS
Extended Tcl provides additional list manipulation commands and
procedures.
intersect lista listb
Procedure to return the logical intersection of two lists. The
returned list will be sorted.
intersect3 lista listb
Procedure to intersects two lists, returning a list containing three
lists: The first list returned is everything in lista that wasn't
in listb. The second list contains the intersection of the two
lists, and the third list contains all the elements that were in
listb but weren't in lista. The returned lists will be sorted.
lassign list var ?var...?
Assign successive elements of a list to specified variables. If
there are more variable names than fields, the remaining variables
are set to the empty string. If there are more elements than
variables, a list of the unassigned elements is returned.
For example,
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lassign {dave 100 200 {Dave Foo}} name uid gid longName
Assigns name to ``dave'', uid to ``100'', gid to ``200'', and
longName to ``Dave Foo''.
lempty list
Determine if the specified list is empty. If empty, 1 is returned,
otherwise, 0 is returned. This command is an alternative to
comparing a list to an empty string.
lmatch ?mode? list pattern
Search the elements of list, returning a list of all elements
matching pattern. If none match, an empty list is returned.
The mode argument indicates how the elements of the list are to be
matched against pattern and it must have one of the following
values:
-exact The list element must contain exactly the same string as
pattern.
-glob Pattern is a glob-style pattern which is matched against each
list element using the same rules as the string match command.
-regexp Pattern is treated as a regular expression and matched
against each list element using the same rules as the regexp
command.
If mode is omitted then it defaults to -glob.
lrmdups list
Procedure to remove duplicate elements from a list. The returned
list will be sorted.
lvarcat var string ?string...?
This command treats each string argument as a list and concatenates
them to the end of the contents of var, forming a a single list.
The list is stored back into var and also returned as the result.
if var does not exist, it is created.
lvarpop var ?indexExpr? ?string?
The lvarpop command pops (deletes) the element indexed by the
expression indexExpr from the list contained in the variable var.
If index is omitted, then 0 is assumed. If string, is specified,
then the deleted element is replaced by string. The replaced or
deleted element is returned. Thus ``lvarpop argv 0'' returns the
first element of argv, setting argv to contain the remainder of the
string.
If the expression indexExpr starts with the string end, then end is
replaced with the index of the last element in the list. If the
expression starts with len, then len is replaced with the length of
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the list.
lvarpush var string ?indexExpr?
The lvarpush command pushes (inserts) string as an element in the
list contained in the variable var. The element is inserted before
position indexExpr in the list. If index is omitted, then 0 is
assumed. If var does not exists, it is created.
If the expression indexExpr starts with the string end, then end is
replaced with the index of the last element in the list. If the
expression starts with len, then len is replaced with the length of
the list. Note the a value of end means insert the string before
the last element.
union lista listb
Procedure to return the logical union of the two specified lists.
Any duplicate elements are removed.
KEYED LISTS
Extended Tcl defines a special type of list referred to as keyed lists.
These lists provided a structured data type built upon standard Tcl
lists. This provides a functionality similar to structs in the C
programming language.
A keyed list is a list in which each element contains a key and value
pair. These element pairs are stored as lists themselves, where the key
is the first element of the list, and the value is the second. The key-
value pairs are refered to as fields. This is an example of a keyed
list:
{{NAME {Frank Zappa}} {JOB {musician and composer}}}
If the variable person contained the above list, then keylget person NAME
would return {Frank Zappa}. Executing the command:
keylset person ID 106
would make person contain
{{ID 106} {NAME {Frank Zappa}} {JOB {musician and composer}}
Fields may contain subfields; `.' is the seperator character. Subfields
are actually fields where the value is another keyed list. Thus the
following list has the top level fields ID and NAME, and subfields
NAME.FIRST and NAME.LAST:
{ID 106} {NAME {{FIRST Frank} {LAST Zappa}}}
There is no limit to the recursive depth of subfields, allowing one to
build complex data structures.
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Keyed lists are constructed and accessed via a number of commands. All
keyed list management commands take the name of the variable containing
the keyed list as an argument (i.e. passed by reference), rather than
passing the list directly.
keyldel listvar key
Delete the field specified by key from the keyed list in the
variable listvar. This removes both the key and the value from the
keyed list.
keylget listvar ?key? ?retvar | {}?
Return the value associated with key from the keyed list in the
variable listvar. If retvar is not specified, then the value will
be returned as the result of the command. In this case, if key is
not found in the list, an error will result.
If retvar is specified and key is in the list, then the value is
returned in the variable retvar and the command returns 1 if the key
was present within the list. If key isn't in the list, the command
will return 0, and retvar will be left unchanged. If {} is
specified for retvar, the value is not returned, allowing the Tcl
programmer to determine if a key is present in a keyed list without
setting a variable as a side-effect.
If key is omitted, then a list of all the keys in the keyed list is
returned.
keylkeys listvar ?key?
Return the a list of the keyes in the keyed list in the variable
listvar. If keys is specified, then it is the name of a key field
who's subfield keys are to be retrieve.
keylset listvar key value ?key2 value2 ...?
Set the value associated with key, in the keyed list contained in
the variable listvar, to value. If listvar does not exists, it is
created. If key is not currently in the list, it will be added. If
it already exists, value replaces the existing value. Multiple
keywords and values may be specified, if desired.
STRING AND CHARACTER MANIPULATION COMMANDS
The commands provide additional functionality to classify characters,
convert characters between character and numeric values, index into a
string, determine the length of a string, extract a range of character
from a string, replicate a string a number of times, and transliterate a
string (similar to the Unix tr program).
ccollate ?-local? string1 string2
This command compares two strings. If returns -1 if string1 is less
than string2, 0 if they are equal amd 1 if string1 is greater than
string2.
If -local is specified, the strings are compared according to the
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collation environment of the current locale.
cequal string1 string2
This command compares two strings for equality. It returns 1 if
string1 and string2 are the identical and 0 if they are not. This
command is a short-cut for string compare and avoids the problems
with string expressions being treated unintentionally as numbers.
cindex string indexExpr
Returns the character indexed by the expression indexExpr (zero
based) from string.
If the expression indexExpr starts with the string end, then end is
replaced with the index of the last character in the string. If the
expression starts with len, then len is replaced with the length of
the string.
clength string
Returns the length of string in characters. This command is a
shortcut for:
string length string
crange string firstExpr lastExpr
Returns a range of characters from string starting at the character
indexed by the expression firstExpr (zero-based) until the character
indexed by the expression lastExpr.
If the expression firstExpr or lastExpr starts with the string end,
then end is replaced with the index of the last character in the
string. If the expression starts with len, then len is replaced
with the length of the string.
csubstr string firstExpr lengthExpr
Returns a range of characters from string starting at the character
indexed by the expression firstExpr (zero-based) for lengthExpr
characters.
If the expression firstExpr or lengthExpr starts with the string
end, then end is replaced with the index of the last character in
the string. If the expression starts with len, then len is replaced
with the length of the string.
ctoken strvar separators
Parse a token out of a character string. The string to parse is
contained in the variable named strvar. The string separators
contains all of the valid separator characters for tokens in the
string. All leading separators are skipped and the first token is
returned. The variable strvar will be modified to contain the
remainder of the string following the token.
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cexpand string
Expand backslash sequences in string to their actual characters. No
other substitution takes place.
ctype ?-failindex var? class string
ctype determines whether all characters in string are of the
specified class. It returns 1 if they are all of class, and 0 if
they are not, or if the string is empty. This command also provides
another method (besides format and scan) of converting between an
ASCII character and its numeric value. The following ctype commands
are available:
ctype ?-failindex var? alnum string
Tests that all characters are alphabetic or numeric characters
as defined by the character set.
ctype ?-failindex var? alpha string
Tests that all characters are alphabetic characters as defined
by the character set.
ctype ?-failindex var? ascii string
Tests that all characters are an ASCII character (a non-
negative number less than 0200).
ctype char number
Converts the numeric value, string, to an ASCII character.
Number must be in the range 0 through 255.
ctype ?-failindex var? cntrl string
Tests that all characters are ``control characters'' as defined
by the character set.
ctype ?-failindex var? digit string
Tests that all characters are valid decimal digits, i.e. 0
through 9.
ctype ?-failindex var? graph string
Tests that all characters within are any character for which
ctype print is true, except for space characters.
ctype ?-failindex var? lower string
Tests that all characters are lowercase letters as defined by
the character set.
ctype ord character
Convert a character into its decimal numeric value. The first
character of the string is converted.
ctype ?-failindex var? space string
Tests that all characters are either a space, horizontal-tab,
carriage return, newline, vertical-tab, or form-feed.
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ctype ?-failindex var? print string
Tests that all characters are a space or any character for
which ctype alnum or ctype punct is true or other ``printing
character'' as defined by the character set.
ctype ?-failindex var? punct string
Tests that all characters are made up of any of the characters
other than the ones for which alnum, cntrl, or space is true.
ctype ?-failindex var? upper string
Tests that all characters are uppercase letters as defined by
the character set.
ctype ?-failindex var? xdigit string
Tests that all characters are valid hexadecimal digits, that is
0 through 9, a through f or A through F.
If -failindex is specified, then the index into string of the first
character that did not match the class is returned in var.
replicate string countExpr
Returns string, replicated the number of times indicated by the
expression countExpr.
translit inrange outrange string
Translate characters in string, changing characters occuring in
inrange to the corresponding character in outrange. Inrange and
outrange may be list of characters or a range in the form `A-M'.
For example:
translit a-z A-Z foobar
returns "FOOBAR".
XPG/3 MESSAGE CATALOG COMMANDS
These commands provide a Tcl interface to message catalogs that are
compliant with the X/Open Portability Guide, Version 3 (XPG/3).
Tcl programmers can use message catalogs to create applications that are
language-independent. Through the use of message catalogs, prompts,
messages, menus and so forth can exist for any number of languages, and
they can altered, and new languages added, without affecting any Tcl or
C source code, greatly easing the maintenance difficulties incurred by
supporting multiple languages.
A default text message is passed to the command that fetches entries from
message catalogs. This allows the Tcl programmer to create message
catalogs containing messages in various languages, but still have a set
of default messages available regardless of the presence of any message
catalogs, and allow the programs to press on without difficulty when no
catalogs are present.
Thus, the normal approach to using message catalogs is to ignore errors
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on catopen, in which case catgets will return the default message that
was specified in the call.
The Tcl message catalog commands normally ignore most errors. If it is
desirable to detect errors, a special option is provided. This is
normally used only during debugging, to insure that message catalogs are
being used. If your Unix implementation does not have XPG/3 message
catalog support, stubs will be compiled in that will create a version of
catgets that always returns the default string. This allows for easy
porting of software to environments that don't have support for message
catalogs.
Message catalogs are global to the process, an application with multiple
Tcl interpreters within the same process may pass and share message
catalog handles.
catopen ?-fail|-nofail? catname
Open the message catalog catname. This may be a relative path name,
in which case the NLSPATH environment variable is searched to find
an absolute path to the message catalog. A handle in the form
msgcatN is returned. Normally, errors are ignored, and in the case
of a failed call to catopen, a handle is returned to an unopened
message catalog. (This handle may still be passed to catgets and
catclose, causing catgets to simply return the default string, as
described above. If the -fail option is specified, an error is
returned if the open fails. The option -nofail specifies the
default behavior of not returning an error when catopen fails to
open a specified message catalog. If the handle from a failed
catopen is passed to catgets, the default string is returned.
catgets catHandle setnum msgnum defaultstr
Retrieve a message form a message catalog. CatHandle should be a Tcl
message catalog handle that was returned by catopen. Setnum is the
message set number, and msgnum is the message number. If the message
catalog was not opened, or the message set or message number cannot
be found, then the default string, defaultstr, is returned.
catclose ?-fail|-nofail? cathandle
Close the message catalog specified by cathandle. Normally, errors
are ignored. If -fail is specified, any errors closing the message
catalog file are returned. The option -nofail specifies the default
behavior of not returning an error. The use of -fail only makes
sense if it was also specified in the call to catopen.
EXTENDED TCL SHELL
tcl ?-qn? ?-f? ?script?|?-c command? ?args?
Tcl starts the interactive Tcl command interpreter. The Tcl shell
provides an environment for writing, debugging and executing Tcl scripts.
The functionality of the Tcl shell can be easily obtained by any
application that includes Tcl.
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The tcl command, issued without any arguments, invokes an interactive Tcl
shell, allowing the user to interact directly with Tcl, executing any Tcl
commands at will and viewing their results.
If script is specified, then the script is executed non-interactively
with any additional arguments, args, being supplied in the global Tcl
variable `argv'. If command is supplied, then this command (or
semicolon-separated series of commands) is executed, with `argv'
containing any args.
The Tcl shell is intended as an environment for Tcl program development
and execution. While it is not a full-featured interactive shell, it
provides a comfortable environment for the interactive development of Tcl
code. Note that the package library code described here overrides the
unknown command provided as part of the standard Berkeley Tcl library
facility, although Tcl source libraries coded to that standard can be
loaded and used by Extended Tcl.
The following command line flags are recognized by the Tcl shell command
line parser:
-q Quick initialization flag. The Tcl initiaization file is not
evaluated and the auto_path variable is not set. Tcl auto-load
libraries will not be available.
-n No procedure call stack dump. The procedure call stack will not be
displayed when an error occurs, only the error message. Useful in
the #! line of already debugged scripts.
-f Takes the next argument as a script for Tcl to source, rather than
entering interactive mode. The -f flag is optional. Normally the
first argument that does not start with a `-' is taken as the script
to execute unless the `-c' option is specified. Any following
arguments are passed to the script via argv, thus any other Tcl
shell command-line flags must precede this option.
-c Take the next argument as a Tcl command to execute. It may contain
series of commands to execute, separated by `;'. Any following
arguments are passed in argv, thus, as with -f, any other Tcl shell
flags must precede this option.
-- Mark the end of the arguments to the Tcl shell. All arguments
following this are passed in the Tcl variable argv. This is useful
to pass arguments without attempting to execute a Tcl script.
The result string returned by a command executed from the Tcl shell
command line is normally echoed back to the user. If an error occurs,
then the string result is displayed, along with the error message. The
error message will be preceded by the string ``Error:''.
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The set command is a special case. If the command is called to set a
variable (i.e. with two arguments), then the result will not be echoed.
If only one argument, the name of a variable, is supplied to set, then
the result will be echoed.
If an unknown Tcl command is entered from the command line, then the Unix
command path, specified in the environment variable PATH, will be
searched for a command of the same name. If the command is found, it
will be executed with any arguments remaining on the Tcl command line
being passed as arguments to the command. This feature is provided to
enhance the interactive environment for developing Tcl scripts.
Automatic execution of programs in this manner is only supported from the
command line, not in script files or in procedures, to reduce confusion
and mistakes while programming in Tcl. Scripts should use the Tcl exec
or system commands to run Unix commands.
The following variables are set and/or used by the Tcl shell.
argv0
Contains the name of the Tcl program specified on the command line
or the name that the Tcl shell was invoked under if no program was
specified. argc Contains a count of the number of argv arguments (0
if none). argv A list containing the arguments passed in from the
command line, excluding arguments used by the Tcl shell. The first
element is the first passed argument, not the program name.
tcl_interactive
Set to 1 if Tcl shell is invoked interactively, or 0 if the Tcl
shell is directly executing a script. Normally checked by scripts
so that they can function as a standalone application if specified
on the command line, but merely load in and not execute if loaded
during an interactive invocation of Tcl.
auto_path
Path to search to locate Tcl scripts. Used by the auto_load command
and the TclX unknown command handler. The path is a Tcl list of
directory names.
tclx_library
Path to the TclX runtime library. If your running the TclX shell or
an appilcation based on it (like wishx), this is the same value
returned by "info library".
tcl_prompt1
Contains code to run to output the prompt used when interactively
prompting for commands.
tcl_prompt2
Contains code to run to output the prompt used when interactively
prompting for continuation of an incomplete command.
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tclx_errorHandler
If this variable is set to the name of a procedure, that procedure
will be call if an uncaught error occurs. The procedure will be
passed a single argument of the error message, however to allow
future expansion, the procedure should have a final argument of
args. The procedure is only called in non-interactive shells. If
the procedure returns normally, the program will just exit without
any error being issued by the shell. Generally the procedure should
exit with a non-zero exit code once the error has been processed.
It is not possible to continue executing the code in which the error
occurred. This is useful for logging errorInfo or e-mailing it to
the maintainer.
TCLXENV
Array that contains information used internally by various Tcl
procedures that are part of the TclX shell. Don't change this array
unless you know what your doing.
When Extended Tcl is installed, the standard runtime files are places in
the Tcl master directory, which is configured when Tcl is built. This
master directory normally contains the Tcl initialization file
(TclInit.tcl), the standard Tcl library file (tcl.tlib) and the help
files. The Tcl master directory is named after the version of Tcl it is
associated with, e.g. /usr/local/tclX/7.4a. The path to the Tcl master
directory is available from the info library command. The location of
the Tcl master directory can be overridden with the TCL_LIBRARY
environment variable.
The first step in initializing the Tcl shell is to locate the Tcl
initialization file, normally TclInit.tcl. If an environment variable
TCLINIT exists, it contains the path to the Tcl initialization file. If
the TCLINIT environment variable is not set, the file TclInit.tcl is used
from the default Tcl master directory.
Tcl then evaulates the Tcl initialization file. The auto_path variable
is initialized to the Tcl master directory and may be augmented by the
intialization file or the application. Other procedures and variables
used by the Extended Tcl shell are also defined by this file.
If the Tcl is invoked interactively, it will source a file named .tclrc
in the user's home directory, if it exists. Tcl is viewed primarily as a
programming language, not an interactive shell, so the .tclrc is intended
for use for loading development utilities, not to support applications,
which should not have to rely on the user's environment in such a manner.
The Extended Tcl Tk shell, wishx, has an additional master directory and
initialization file. It use the environment variable TK_LIBRARY to
override the default location of the Tk master directory.
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TclX(3Tcl)TclX(3Tcl)HELP FACILITY
The help facility allows one to look up help pages which where extracted
from the standard Tcl manual pages and Tcl scripts during Tcl
installation. Help files are structured as a multilevel tree of subjects
and help pages. Help files are found by searching directories named help
in the directories listed in the auto_path variable. All of the files in
the list of help directories form a virtual root of the help tree. This
method allows multiple applications to provide help trees without having
the files reside in the same directory.
The help facility can be accessed in two ways, as interactive commands in
the Extended Tcl shell or as an interactive Tk-based program (if you have
built Extended Tcl with Tk).
To run the Tk-based interactive help program:
tclhelp ?addpaths?
Where addpaths are additional paths to search for help directories. By
default, only the auto_path used by tclhelp is search. This will result
in help on Tcl, Extended Tcl and Tk.
The following interactive Tcl commands and options are provided with the
help package:
help
Help, without arguments, lists of all the help subjects and pages
under the current help subject.
help subject
Displays all of help pages and lower level subjects (if any exist)
under the subject subject.
help subject/helppage
Display the specified help page. The help output is passed through
a simple pager if output exceeds 23 lines, pausing waiting for a
return to be entered. If any other character is entered, the output
is terminated.
helpcd ?subject?
Change the current subject, which is much like the Unix current
directory. If subject is not specified, return to the top-level of
the help tree. Help subject path names may also include ``..''
elements.
helppwd
Displays the current help subject.
help help | ?
Displays help on the help facility at any directory level.
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apropos pattern
This command locates subjects by searching their one-line
descriptions for a pattern. Apropos is useful when you can remember
part of the name or description of a command, and want to search
through the one-line summaries for matching lines. Full regular
expressions may be specified (see the regexp command).
TCL LOADABLE LIBRARIES AND PACKAGES
Extended Tcl supports standard Tcl tclIndex libraries and package
libraries. A package library file can contain multiple independent Tcl
packages. A package is a named collection of related Tcl procedures and
initialization code.
The package library file is just a regular Unix text file, editable with
your favorite text editor, containing packages of Tcl source code. The
package library file name must have the suffix .tlib. An index file with
the suffix .tndx, corresponding to the package library. The .tndx will
be automatically created by Tcl whenever it is out of date or missing
(provided there is write access to the directory.
The variable auto_path contains a list of directories that are searched
for libraries. The first time an unknown command trap is take, the
indexes for the libraries are loaded into memory. If the auto_path
variable is changed during execution of a program, it will be re-
searched. Only the first package of a given name found during the
execution of a program is loaded. This can be overridden with
loadlibindex command.
The start of a package is delimited by:
#@package: package_name proc1 ?..procN?
These lines must start in column one. Everything between the #@package:
keyword and the next #@package: keyword or a #@packend keyword, or the
end of the file, becomes part of the named package. The specified
procedures, proc1..procN, are the entry points of the package. When a
command named in a package specification is executed and detected as an
unknown command, all code in the specified package will be sourced. This
package should define all of the procedures named on the package line,
define any support procedures required by the package and do any
package-specific initialization. Packages declarations maybe continued
on subsequent lines using standard Tcl backslash line continuations. The
#@packend keyword is useful to make sure only the minimum required
section of code is sourced. Thus for example a large comment block at
the beginning of the next file won't be loaded.
Care should be taken in defining package_name, as the first package found
in the path by with a given name is loaded. This can be useful in
developing new version of packages installed on the system.
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For example, in a package source file, the presence of the following
line:
#@package: directory_stack pushd popd dirs
says that the text lines following that line in the package file up to
the next package line or the end of the file is a package named
directory_stack and that an attempt to execute either pushd, popd or dirs
when the routine is not already defined will cause the directory_stack
portion of the package file to be loaded.
PACKAGE LIBRARY MANAGEMENT COMMANDS
Several commands are available for building and managing package
libraries. Commands that are extended versions of the standard Tcl
library commands are listed here. All of the standard Tcl library
management commands and variables are also supported.
auto_commands ?-loaders?
Lists the names of all known loadable procedures and commands
procedures. If -loaders is specified, the command that will be
executed to load the command will also be returned.
buildpackageindex libfilelist
Build index files for package libraries. The argument libfilelist
is a list of package libraries. Each name must end with the suffix
.tlib. A corresponding .tndx file will be built. The user must
have write access to the directory containing each library.
convert_lib tclIndex packagelib ?ignore?
Convert a Ousterhout style tclIndex index file and associate source
files into a package library packagelib. If packagelib does not
have a .tlib extension, one will be added. Any files specified in
tclIndex that are in the list ignore will be skipped. Files listed
in ignore should just be the base file names, not full paths.
auto_load ?command?
Attempt to load the specified command from a loadable library.
loading the package containing the procedure. If the package
indexes have not been loaded for all package libraries in auto_path,
they will be loaded. Out-of-date library indexes will be rebuilt if
they are writable. The procedure returns 1 if the command was
sucessfully loaded, or 0 if it was not.
Duplicated package names are skipped, the first package of a given
name found in the path is loaded. If the auto_path has changed
since the last load, indexes will be reloaded (duplicate packages
will not be redefined).
If command is not specified, the indexes will be loaded, if they
have not alreay been loaded or if the auto_path variable has
changed, but no command will be loaded.
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This command overrides the standard Tcl procedure of the same name.
loadlibindex libfile.tlib
Load the package library index of the library file libfile (which
must have the suffix .tlib). Package library indexes along the
auto_path are loaded automatically on the first demand_load; this
command is provided to explicitly load libraries that are not in the
path. If the index file (with a .tndx suffix) does not exists or is
out of date, it will be rebuilt if the user has directory
permissions to create it. If a package with the same name as a
package in libfile.tlib has already been loaded, its definition will
be overridden by the new package. However, if any procedure has
actually been used from the previously defined package, the
procedures from libfile.tlib will not be loaded.
This command will also load an index built by mkindex.tcl program
supplied with standard Tcl. This file must be named "tclIndex".
auto_packages ?-location?
Returns a list of the names of all defined packages. If -location is
specified, a list of pairs of package name and the .tlib path name,
offset and length of the package within the library.
auto_load_file file
Source a file, as with the source command, except search auto_path
for the file.
searchpath path file
Search all directories in the specified path, which is a Tcl list,
for the specified file. Returns the full path name of the file, or
an empty string if the requested file could not be found.
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