GETOPTS(1)GETOPTS(1)NAME
getopts, getoptcvt - parse command options
SYNOPSIS
getopts optstring name [arg ...]
/usr/lib/getoptcvt [-b] file
DESCRIPTION
getopts is a built-in command to sh(1) used to parse positional
parameters and to check for legal options. It supports all applicable
rules of the command syntax standard (see Rules 3-10, intro(1)). It
should be used in place of the getopt(1) command. See the WARNINGS
section below.
optstring must contain the option letters the command using getopts will
recognize; if a letter is followed by a colon, the option is expected to
have an argument, or group of arguments, which must be separated from it
by white space.
Each time it is invoked, getopts will place the next option in the shell
variable name and the index of the next argument to be processed in the
shell variable OPTIND. Whenever the shell or a shell procedure is
invoked, OPTIND is initialized to 1.
When an option requires an option-argument, getopts places it in the
shell variable OPTARG.
If an illegal option is encountered, ? will be placed in name.
When the end of options is encountered, getopts exits with a non-zero
exit status. The special option ``--'' may be used to delimit the end of
the options.
By default, getopts parses the positional parameters. If extra arguments
(arg ...) are given on the getopts command line, getopts will parse them
instead.
/usr/lib/getoptcvt reads the shell script in file, converts it to use
getopts(1) instead of getopt(1), and writes the results on the standard
output.
-b the results of running /usr/lib/getoptcvt will be portable to
earlier releases of the UNIX system. /usr/lib/getoptcvt modifies
the shell script in file so that when the resulting shell script is
executed, it determines at run time whether to invoke getopts(1) or
getopt(1).
So all new commands will adhere to the command syntax standard described
in intro(1), they should use getopts(1) or getopt(3C) to parse positional
parameters and check for options that are legal for that command (see the
WARNINGS section below).
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GETOPTS(1)GETOPTS(1)EXAMPLE
The following fragment of a shell program shows how one might process the
arguments for a command that can take the options a or b, as well as the
option o, which requires an option-argument:
while getopts abo: c
do
case $c in
a | b) FLAG=$c;;
o) OARG=$OPTARG;;
\?) echo $USAGE
exit 2;;
esac
done
shift `expr $OPTIND - 1`
This code will accept any of the following as equivalent:
cmd -a -b -o "xxx z yy" file
cmd -a -b -o "xxx z yy" -- file
cmd -ab -o xxx,z,yy file
cmd -ab -o "xxx z yy" file
cmd -o xxx,z,yy -b -a file
SEE ALSOintro(1), sh(1), getopt(3C)WARNINGS
Although the following command syntax rule (see intro(1)) relaxations are
permitted under the current implementation, they should not be used
because they may not be supported in future releases of the system. As
in the EXAMPLE section above, a and b are options, and the option o
requires an option-argument:
cmd -aboxxx file (Rule 5 violation: options with
option-arguments must not be grouped with other options)
cmd -ab -oxxx file (Rule 6 violation: there must be
white space after an option that takes an option-argument)
Changing the value of the shell variable OPTIND or parsing different sets
of arguments may lead to unexpected results.
DIAGNOSTICS
getopts prints an error message on the standard error when it encounters
an option letter not included in optstring.
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