Intro(C)
Intro --
introduces UNIX commands
Syntax
Unless otherwise noted, commands described in the ``Syntax'' 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:
[ ]-
Surrounds an option or cmdarg that is not
mandatory.
...-
Indicates multiple occurrences of the option or
cmdarg.
name-
The name of an executable file.
option-
This is always preceded by a ``-'' and may be in one of the two
following forms:
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 in the following
text).
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-
Pathname (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 use them.
getopts(C)
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 be done by the
command itself.
-
Command names (name above) must be between two and nine
characters long.
-
Command names must include only lowercase letters and digits.
-
Option names (option above) must be one character long.
-
All options must be preceded by
``-''.
-
Options with no arguments may be grouped after a single
``-''.
-
The first option-argument (optarg above) following an
option must be preceded by white space.
-
Option-arguments cannot be optional.
-
Groups of option-arguments following an option must either be
separated by commas or separated by white space and quoted (for
example, -o xxx,z,yy or -o "xxx z yy").
-
All options must precede operands (cmdarg above) on the
command line.
-
``--'' may be used to indicate the end of the options.
-
The order of the options relative to one another should not matter.
-
The relative order of the operands (cmdarg above) may
affect their significance in ways determined by the command with
which they appear.
-
``-'' preceded and followed by white space should only be used to
mean standard input.
Description
This section describes the use of the individual commands available
in the UNIX Operating System. Each command in this section is
labeled with a C (Command) for easy reference from other
volumes. (Commands labeled with the letters ``CP''
(Programming commands) are documented as part of the Development
System. The Development System is an optional supplemental package
to the standard Operating System.)
For example,
date(C)
indicates a reference to a discussion of the date command
in the C section;
cc(CP)
indicates a reference to a discussion of the cc command in
the Development System.
The ``ADM'' (Administration) section contains descriptions
of the commands used to maintain and administer the operating
system. Other reference sections include the ``M''
(Miscellaneous) section, the ``S'' (System services)
section, the ``HW'' (Hardware) section, and the
``F'' (File format) section.
Exit values
Upon termination, a command exits and returns a value to the calling
shell. This exit value is used within shell scripts to determine
whether the command completed successfully.
A command normally returns 0 (zero) for normal termination with no
error; a non-zero exit value indicates problems such as incorrect
parameters, and bad or missing data.
An exit value may sometimes be referred to as ``exit code'', ``exit
status,'' or ``return value.'' Exit values are described only where
special conventions are involved.
Diagnostics
This section describes the likely cause of error or information
messages that may be output by a command. This section does not
document system service messages which arise because of the failure
of an underlying system call (see
messages(M)
for details of system service messages).
Warning
This section warns of the possible adverse consequences of using the
command if certain precautions are not taken. These consequences may
include loss of data, extended system down time, degradation of
system performance, or damage to hardware.
Limitations
This section details aspects of usage, or limits of applicability of
a command that a user should note. There may be reasons in the
software or hardware why a command will fail in certain
circumstances. These reasons may include internal limits on table
size or number of temporary variables.
Authorization
This section documents if a command, normally only usable by the
root user, may be invoked by trusted users if this is
allowed by the
authorize(F)
file.
See also
authorize(F),
exit(S),
getopt(S),
getopts(C),
messages(M),
wait(S)
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003