#!/bin/bash

show_help() {
    echo "Usage: $0 [--files|-f files]"
    echo "Options:"
    echo "  --help          | -h (Optional) Display help information on how to use this script"
    echo "  --key           | -k (Required) Specify the key's name"
    echo "  --new-value     | -v (Required) Specify the new value for the key"
    echo "  --file-path     | -f (Required) Specify the file's path"
}

key=''
new_value=''
file_path=''

while [ "$#" -gt 0 ]; do
    case "$1" in
        --help|-h)      show_help; exit ;;
        --key|-k)       key="$2"; shift 2;;
        --new-value|-v) new_value="$2"; shift 2;;
        --file-path|-f) file_path="$2"; shift 2;;
        *) shift ;;
    esac
done

old_value=`cat $file_path | grep $key | awk -F= '{print $2}'`
sed -i "s/$old_value/$new_value/g" $file_path