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NAME
intro - introduction to commands and application programs
DESCRIPTION
This section describes, in alphabetical order, user commands
and utilities that are part of the operating system.
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 (Always preceded by a ``-''.)
noargletter... or,
argletter optarg[,...]
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 requir-
ing an option-argument.
optarg An option-argument (character string) satisfy-
ing 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 indi-
cating 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 procedures to parse positional
parameters and to check for legal options. It supports
Rules 3-10 below. The enforcement of the other rules must
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be done by the command itself.
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.
SEE ALSO
getopts(1).
exit(2), wait(2), getopt(3C) in the Programmer's Reference
Manual.
DIAGNOSTICS
Upon termination, each command returns two bytes of status,
one supplied by the system and giving the cause for termina-
tion, and (in the case of ``normal'' termination) one sup-
plied by the program [see wait(2) and exit(2)]. The former
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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 conven-
tions 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 con-
fused upon encountering a null character (the string termi-
nator) within a line.
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