Question

how I can create this small script?

For example:

~$ script.sh -b my small string... other things -a other string -c any other string ant etc

I want only string, every have a mode.

-b
my small string... other things
-a
other string
-c
any other string ant etc

Anyone know how implements it?

Thanks

Answer 1

Here’s a very simple command-line argument loop. The command-line arguments are $1, $2, etc., and the number of command-line arguments is $#. The shift command discards the arguments after we’re done with them.

#!/bin/bash

while [[ $# -gt 0 ]]; do
    case "$1" in
        -a) echo "option $1, argument: $2"; shift 2;;
        -b) echo "option $1, argument: $2"; shift 2;;
        -c) echo "option $1, argument: $2"; shift 2;;
        -*) echo "unknown option: $1"; shift;;
        *)  echo "$1"; shift;;
    esac
done

UNIX commands normally expect you to quote multi-word arguments yourself so they show up as single arguments. Usage would look like:

~$ script.sh -b 'my small string... other things' -a 'other string' -c 'any other string ant etc'
option -b, argument: my small string... other things
option -a, argument: other string
option -c, argument: any other string ant etc

Notice how I’ve quoted the long arguments.

I don’t recommend it, but if you really want to pass in multiple words on the command-line but treat them as single arguments, you’ll need something a little more complicated:

#!/bin/bash

while [[ $# -gt 0 ]]; do
    case "$1" in
        -a) echo "option: $1"; shift;;
        -b) echo "option: $1"; shift;;
        -c) echo "option: $1"; shift;;

        -*) echo "unknown option: $1"; shift;;

        *)  # Concatenate arguments until we find the next `-x' option.
            OTHER=()

            while [[ $# -gt 0 && ! ( $1 =~ ^- ) ]]; do
                OTHER+=("$1")
                shift
            done

            echo "${OTHER[@]}"
    esac
done

Example usage:

~$ script.sh -b my small string... other things -a other string -c any other string ant etc
option: -b
my small string... other things
option: -a
other string
option: -c
any other string ant etc

Again, though, this usage is not recommended. It goes against UNIX norms and conventions to concatenate arguments like this.