Using getopts to process long and short command line options

Question

I wish to have long and short forms of command line options invoked using my shell script.

I know that getopts can be used, but like in Perl, I have not

Answer 1

getopts "could be used" for parsing long options as long as you don't expect them to have arguments...

Here's how to:

$ cat > longopt
while getopts 'e:-:' OPT; do
  case $OPT in
    e) echo echo: $OPTARG;;
    -) #long option
       case $OPTARG in
         long-option) echo long option;;
         *) echo long option: $OPTARG;;
       esac;;
  esac
done

$ bash longopt -e asd --long-option --long1 --long2 -e test
echo: asd
long option
long option: long1
long option: long2
echo: test

If you try to use OPTIND for getting a parameter for the long option, getopts will treat it as the first no optional positional parameter and will stop parsing any other parameters. In such a case you'll be better off handling it manually with a simple case statement.

This will "always" work:

$ cat >longopt2
while (($#)); do
    OPT=$1
    shift
    case $OPT in
        --*) case ${OPT:2} in
            long1) echo long1 option;;
            complex) echo comples with argument $1; shift;;
        esac;;

        -*) case ${OPT:1} in
            a) echo short option a;;
            b) echo short option b with parameter $1; shift;;
        esac;;
    esac
done


$ bash longopt2 --complex abc -a --long -b test
comples with argument abc
short option a
short option b with parameter test

Albeit is not as flexible as getopts and you have to do much of the error checking code yourself within the case instances...

But it is an option.