getopt - parse command options
getopt optstring args
getopt is used to break up options in command lines for easy parsing
by shell procedures and to check for legal options. optstring is a
string of recognized option letters (see getopt(3C)). If a letter is
followed by a colon, the option is expected to have an argument which
may or may not be separated from it by white space.
The positional parameters ($1 $2 ...) of the shell are reset so that
each option is preceded by a - and is in its own positional parameter;
each option argument is also parsed into its own positional parameter.
getopt recognizes two hyphens (--) to delimit the end of the options.
If absent, getopt places -- at the end of the options.
The most common use of getopt is in the shell's set command (see the
example below) where getopt converts the command line to a more easily
parsed form. getopt writes the modified command line to the standard
LC_MESSAGES determines the language in which messages are displayed.
If LC_MESSAGES is not specified in the environment or is set to the
empty string, the value of LANG is used as a default for each
unspecified or empty variable.
If LANG is not specified or is set to the empty string, a default of
"C" (see lang(5)) is used instead of LANG. If any
internationalization variable contains an invalid setting, getopt
behaves as if all internationalization variables are set to "C". See
International Code Set Support
Single-byte and multi-byte character code sets are supported.
getopt prints an error message on the standard error when it
encounters an option letter not included in optstring.
The following code fragment processes the arguments for a command that
can take the options a or b, and the option o which requires an
Hewlett-Packard Company - 1 - HP-UX Release 11i: November 2000
set -- `getopt abo: $*`
if [ $? -ne 0 ]; then
while [ $# -gt 0 ]; do
case $1 in
-a | -b)
This code accepts any of the following as equivalent:
cmd -aoarg file file
cmd -a -o arg file file
cmd -oarg -a file file
cmd -a -oarg -- file file
getopt option arguments must not be null strings nor contain embedded
Hewlett-Packard Company - 2 - HP-UX Release 11i: November 2000