How to get the agrument after the command using GETOPTS in BASH - bash

Question

Example of script usage
./myscript --p 1984 --n someName
#!/bin/bash
while getopts :npr opt
do
case $opt in
n ) echo name= ??? ;;
p ) echo port= ??? ;;
r ) echo robot= "Something" ;;
? ) echo "Useage: -p [#]" ;;
esac
done
How to I access the argument following the command option?
Moreover, if i type: ./myscript --p 1985 I would like to know how ot echo 1985 back and work with that argument.

Answer 1

In bash, see help getopts: "When an option requires an argument, getopts places that argument into the shell variable OPTARG."
usage() { echo "Usage: $(basename $0) -n name -p port -r"; exit; }
while getopts :n:p:r opt # don't forget the colons for opts that take an arg
do
case $opt in
n ) name="$OPTARG" ;;
p ) port="$OPTARG" ;;
r ) robot=chicken ;;
? ) usage ;;
esac
done
shift $(( OPTIND - 1 ))
echo "the name is $name"
echo "the port is $port"
I'm sure you could google around for a solution to parse options in bash. Here's a couple minutes' effort:
#!/bin/bash
usage() { echo foo; exit; }
while [[ $1 == -* ]]; do
case "$1" in
--) shift 1; break ;;
-p|--p|--port) port="$2"; shift 2;;
-n|--n|--name) name="$2"; shift 2;;
*) echo "unknown option: $1"; usage;;
esac
done
echo "the name is $name"
echo "the port is $port"
echo "the rest of the args are:"; ( IFS=,; echo "$*" )
And a test,
$ bash longopts.sh --port 1234 --bar a b c
unknown option: --bar
foo
$ bash longopts.sh --port 1234 a b c
the name is
the port is 1234
the rest of the args are:
a,b,c