Bash Shell Script - Check for a flag and grab its value

Question

I am trying to make a shell script which is designed to be run like this:

script.sh -t application

Firstly, in my script I want to check to see

Answer 1

You should read this getopts tutorial.

Example with -a switch that requires an argument :

#!/bin/bash

while getopts ":a:" opt; do
  case $opt in
    a)
      echo "-a was triggered, Parameter: $OPTARG" >&2
      ;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      exit 1
      ;;
    :)
      echo "Option -$OPTARG requires an argument." >&2
      exit 1
      ;;
  esac
done

Like greybot said(getopt != getopts) :

The external command getopt(1) is never safe to use, unless you know it is GNU getopt, you call it in a GNU-specific way, and you ensure that GETOPT_COMPATIBLE is not in the environment. Use getopts (shell builtin) instead, or simply loop over the positional parameters.