Passing Arguments to Your Script

#!/bin/bash
######################################################################
#Copyright (C) 2022  Kris Occhipinti
#https://filmsbykris.com

#This program is free software: you can redistribute it and/or modify
#it under the terms of the GNU General Public License as published by
#the Free Software Foundation, either version 3 of the License, or
#(at your option) any later version.

#This program is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU General Public License for more details.

#You should have received a copy of the GNU General Public License
#along with this program.  If not, see <http://www.gnu.org/licenses/>.
######################################################################

url="$1"

function error(){
  echo "Usage: $0 <url>"
  echo "Example: $0 'https://www.youtube.com/watch?v=cgKL39zpgm4'"
  exit 1
}

[[ "$url" == "http"* ]] || url="$(xclip -o)"
[[ "$url" == "http"* ]] || read -p "Please Enter a URL: " url
[[ "$url" == "http"* ]] || error

youtube-dl "$url"