Unix & Linux
bash shell-script shell scripting parameter
Updated Sat, 11 Jun 2022 13:36:11 GMT

Parsing an array as one of many keyword parameter in a bash script


I have a bash script (script.sh) that takes in many parameters in the format --keyword value. It is read in when the script is invoked with the following lines:

# Get our arguments using flags,
while [[ "$#" > 1 ]]; do
        case "$1" in
            "--h")
                help
                exit
                ;;
            "--param1") param1="$2"; shift 2;;
            "--param2") param2="$2"; shift 2;;
            "--param3") param3="$2"; shift 2;;
        esac
done

Suppose I want to introduce a --param4 that takes in one or many parameters instead of just one. e.g.

bash ./script.sh --param1 a --param2 b --param3 c --param4 x y z

The order shouldn't matter theoretically matter, so after hitting param4, we should keep pulling in the next parameters until we hit another --param flag.

How can I actually parse this list? The end goal is to iterate through param4 as feed it as a parameter to a Python script. (something like):

for item in $param4; do
    python my_python_script.py --${item}
done


Solution

Try this:

usage(){ echo 'usage: ...'; exit 2; } 
while [ "$#" -gt 1 ]; do
        case $1 in
        --param1) param1=$2; shift 2;;
        --param2) param2=$2; shift 2;;
        --param3) param3=$2; shift 2;;
        --param4)
                shift
                while [ "$#" -gt 0 ]; do
                        case $1 in
                        --param*) break;;
                        *) param4+=("$1"); shift;;
                        esac
                done
                ;;
        *) usage ;;
        esac
done
[ "$#" -gt 0 ] && usage
for p in "${param4[@]}"; do
    echo python "--$p"
done





References