shell script provides advanced output of `pkg-config`

pkg.sh

#!/bin/bash

action=$1
shift 1

no_flag=0
quote=0

while getopts "nqf:" opt; do
    case ${opt} in
        n)
        no_flag=1
        ;;
        q)
        quote=1
        ;;
        *)
        ;;
    esac
done
shift $((OPTIND -1))

function _cmd() {
    local flag=$1
    shift 1
    local base=""
    local array=()
    for pkg in "$@"; do
        IFS=' ' read -r -a arr <<< "$(pkg-config "$flag" "$pkg")"
        for i in "${arr[@]}"; do
            array+=("$i")
        done
    done

    base="$(echo "${array[@]}" | tr ' ' '\n' | sort -u)"

    if [ $quote -eq 1 ]; then
        base="$(echo "$base" | xargs -d '\n' -I {} echo '"{}",')"
    fi
    echo "$base"
}

ret=""
case $action in
    cflags)
    ret="$(_cmd --cflags "$@")"
    ;;
    libs)
    ret="$(_cmd --libs "$@")"
    ;;
    static)
    ret="$(_cmd --static "$@")"
    ;;
    include)
    ret="$(_cmd --cflags-only-I "$@")"
    if [ $no_flag -eq 1 ]; then
        ret="${ret//-I/}"
    fi
    ;;
    *)
    ;;
esac

echo "$ret"