GETOPTS(1-SysV) RISC/os Reference Manual GETOPTS(1-SysV)
NAME
getopts, getoptcvt - parse command options
SYNOPSIS
getopts optstring name [arg ...]
/usr/lib/getoptcvt [-b] file
DESCRIPTION
getopts is used by shell procedures 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 WARNING, 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 argu-
ment to be processed in the shell variable OPTIND. Whenever
the shell or a shell procedure is invoked, OPTIND is ini-
tialized 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 instead of getopt(1), and writes the
results on the standard output.
-b the results of running /usr/lib/getoptcvt will be port-
able 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 or
getopt(1).
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GETOPTS(1-SysV) RISC/os Reference Manual GETOPTS(1-SysV)
So all new commands will adhere to the command syntax stan-
dard described in intro(1), they should use getopts or
getopt(3) to parse positional parameters and check for
options that are legal for that command (see WARNINGS,
below).
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 ALSO
intro(1), sh(1).
getopt(3) in the Programmer's Reference Manual.
WARNING
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.
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GETOPTS(1-SysV) RISC/os Reference Manual GETOPTS(1-SysV)
DIAGNOSTICS
getopts prints an error message on the standard error when
it encounters an option letter not included in optstring.
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