topic Re: getopt in Operating System - Linux

getopt

itai weisman — Sun, 02 Sep 2007 04:06:12 GMT

Hello ppl,
on unix shell scripting (bash, ksh, sh)
does anyone know how can I use getopt in order to examine command line parameters?
I couldn't find any helpfull info on man pages or other places on the web...
thanks
Itai.

Re: getopt

Steven E. Protter — Sun, 02 Sep 2007 05:14:42 GMT

Shalom,

Example:

while getopts d:n:f:r:l: opt
do
case "$opt" in
d) dflg=1
DELAY=$OPTARG;;
r) rflg=1
RUNS=$OPTARG;;
n) nflg=1
NUM=$OPTARG;;
l) lflg=1
LF=$OPTARG;;
f) nflg=1
FILTER=$OPTARG;;
?) out_help
exit ;;
esac
done 2>/dev/null

http://www.hpuxconsulting.com/mem.mon

This script is in it's late beta stages, a memory leak monitor for HP-UX, Solaris and Linux.

SEP

Re: getopt

itai weisman — Sun, 02 Sep 2007 05:48:48 GMT

ok,
if I have two switches that are conflicts each other (like -l and -L on lvcreate command...) how can I check it with getopts?

Re: getopt

James R. Ferguson — Sun, 02 Sep 2007 08:09:44 GMT

Hi:

> if I have two switches that are conflicts each other (like -l and -L on lvcreate command...) how can I check it with getopts?

Notice in the example given that as each switch is seen that a variable is set denoting that. Hence, after 'getopt' runs, write tests like:

if [ "$l_flag" = 1 -a "$L_flag" = 1 ]; then
print -u2 "Error: '-l' and '-L' are mutually exclusive"
fi

...

Since errors should be directed to STDERR I used 'print -u2' to target that file descriptor (FD2).

Regards!

...JRF...

Re: getopt

Peter Nikitka — Sun, 02 Sep 2007 11:59:09 GMT

Hi,

in addition to SEP and JRF:
If you have to deal with plain parameters as well, don't forget to reset the argument list.

while getopts :al:L:n op
do
case $op in
a|n) ${op}flag=y ;;
l) ${op}flag=$OPTIND
if [ "$Lflag" ]; then print -u2 'mutually exclusive option -l|-L ...'; exit 2;;
L) ${op}flag=$OPTIND
if [ "$lflag" ]; then print -u2 'mutually exclusive option -l|-L ...'; exit 2;;
?) print -u usage ;;
esac
done
# reset arglist
shift $((OPTIND-1))

typeset -i p=0
for i # all remaining parameters
do
print param$((p+=1))="'$i'"
done

mfG Peter

Re: getopt

Dennis Handly — Sun, 02 Sep 2007 12:37:22 GMT

There is info under ksh(1) and sh-posix(1). It also has its own man page, getopt(1) and getopts(1), getopt(3):
http://docs.hp.com/en/B2355-60130/getopts.1.html
http://docs.hp.com/en/B2355-60130/getopt.1.html
http://docs.hp.com/en/B2355-60130/getopt.3C.html

Re: getopt

itai weisman — Sun, 02 Sep 2007 13:43:34 GMT

can I use getopts with switches that has more than one character? (like -itai)

Re: getopt

Dennis Handly — Sun, 02 Sep 2007 14:06:37 GMT

>can I use getopts with switches that has more than one character? (like -itai)

Not directly. You would have to have -i with a parm that is "tai". Or you would have to leave out -i and process it as an illegal option.

Re: getopt

James R. Ferguson — Sun, 02 Sep 2007 14:13:57 GMT

Hi (again) Itai:

> can I use getopts with switches that has more than one character? (like -itai)

No, 'getopt' and 'getopts' are single-character oriented. Perl offers a 'Getopt::Long' module where options are introduced with double dashes and can have long names, like '--help' or '--verbose'.

Regards!

...JRF...

Re: getopt

dirk dierickx — Mon, 03 Sep 2007 02:04:29 GMT

read this excellent guide on shelldorado for some more info.

http://www.shelldorado.com/goodcoding/cmdargs.html

Re: getopt

Peter Nikitka — Mon, 03 Sep 2007 04:23:59 GMT

Hi,

in (another) addition to JRF regarding the usage of multi-character-options:
If you supply somthing like '-ita' AND NONE of the options is defined to get a parameter, all of the options i,t,a are set.
Try with my (corrected) testscript:

#!/usr/bin/ksh
while getopts :al:L:n op
do
case $op in
a|n) eval ${op}flag=y ;;
l) eval ${op}flag=$OPTARG
if [ "$Lflag" ]; then print -u2 'mutually exclusive option -l|-L ...'; exit 2;fi ;;
L) eval ${op}flag=$OPTARG
if [ "$lflag" ]; then print -u2 'mutually exclusive option -l|-L ...'; exit 2;fi ;;
?) print -u usage ;;
esac
done
# reset arglist
shift $((OPTIND-1))

typeset -i p=0
for i # all remaining parameters
do
print param$((p+=1))="'$i'"
done
print Flags:
set | fgrep flag=

Example:
opt.ksh -anL val
Flags:
Lflag=val
aflag=y
nflag=y

mfG Peter