INTRO(1)INTRO(1)NAMEintro - introduction to commands, application programs, and programming
commands.
DESCRIPTION
This section describes, in alphabetical order, publicly-accessible
commands. Certain distinctions of purpose are made in the headings:
(1) Commands of general utility.
(1C) Commands for communication with other systems.
(1G) Graphics utilities.
Manual Page Command Syntax
Unless otherwise noted, commands described in the SYNOPSIS section of a
manual page accept options and other arguments according to the following
syntax and should be interpreted as explained below.
name [ -option ... ] [ cmdarg ... ]
where:
[ ] Surround an option or cmdarg that is not required.
... Indicates multiple occurrences of the option or cmdarg.
name The name of an executable file.
option This is either
noargletter...
or
argletter optarg[,...]
It is always preceded by a ``-''.
noargletter
A single letter representing an option without an option-
argument. Note that more than one noargletter option can be
grouped after one ``-'' (Rule 5, below).
argletter
A single letter representing an option requiring an option-
argument.
optarg An option-argument (character string) satisfying a preceding
argletter. Note that groups of optargs following an
argletter must be separated by commas, or separated by white
space and quoted (Rule 8, below).
cmdarg Path name (or other command argument) not beginning with
``-'', or ``-'' by itself indicating the standard input.
Command Syntax Standard: Rules
These command syntax rules are not followed by all current commands, but
all new commands will obey them. getopts(1) should be used by all shell
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INTRO(1)INTRO(1)
procedures to parse positional parameters and to check for legal options.
It supports Rules 3-10 below. The enforcement of the other rules must be
done by the command itself.
Since almost all commands are run via the shells ( bsh(1),sh(1),csh(1),
ksh(1),and tcsh(1)) diagnostic messages may be issued by the shells,
prior to, or even instead of, the command itself being executed. A
common case is too many arguments to the command. See the manual page
for your shell for details.
1. Command names (name above) must be between two and nine
characters long.
2. Command names must include only lower-case letters and digits.
3. Option names (option above) must be one character long.
4. All options must be preceded by ``-''.
5. Options with no arguments may be grouped after a single ``-''.
6. The first option-argument (optarg above) following an option
must be preceded by white space.
7. Option-arguments cannot be optional.
8. Groups of option-arguments following an option must either be
separated by commas or separated by white space and quoted
(e.g., -o xxx,z,yy or -o "xxx z yy").
9. All options must precede operands (cmdarg above) on the command
line.
10. ``--'' may be used to indicate the end of the options.
11. The order of the options relative to one another should not
matter.
12. The relative order of the operands (cmdarg above) may affect
their significance in ways determined by the command with which
they appear.
13. ``-'' preceded and followed by white space should only be used
to mean standard input.
Throughout the manual pages there are references to TMPDIR, BINDIR,
INCDIR, LIBDIR, and LLIBDIR. These represent directory names whose
value is specified on each manual page as necessary. For example,
TMPDIR might refer to /tmp or /usr/tmp. These are not environment
variables and cannot be set. (There is also an environment variable
called TMPDIR which can be set. See tmpnam(3S).)
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INTRO(1)INTRO(1)SEE ALSOgetopts(1), exec(2), exit(2), wait(2), getopt(3C).
DIAGNOSTICS
Upon termination, each command returns two bytes of status, one supplied
by the system and giving the cause for termination, and (in the case of
``normal'' termination) one supplied by the program (see wait(2) and
exit(2)). The former byte is 0 for normal termination; the latter is
customarily 0 for successful execution and non-zero to indicate troubles
such as erroneous parameters, or bad or inaccessible data. It is called
variously ``exit code'', ``exit status'', or ``return code'', and is
described only where special conventions are involved.
WARNINGS
Some commands produce unexpected results when processing files containing
null characters. These commands often treat text input lines as strings
and therefore become confused upon encountering a null character (the
string terminator) within a line.
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