ITS_ Best ever url video download shell script

#!/bin/bash
####################################
#                      #
# START                #
# g0ne_@p0stal <v1ral_ITS>         #
# ImPerialTeKSolutions@outlook.com #
#                  #
####################################

needed_tool='youtube-dl yad kdialog ffmpeg'
require_tools ()
{
    local NOT_AVAIL=""
    for TOOL in $needed_tool; do
        if [ "`which $TOOL 2> /dev/null`" == "" ]; then NOT_AVAIL="$NOT_AVAIL $TOOL"; fi
    done
    if [[ "$NOT_AVAIL" != "" ]]; then
        echo "ERROR: The following required tool(s) cannot be found: $NOT_AVAIL"
        exit 3
    fi
}

# Check If Package Downloaded
require_tools

# Download URL
read URL < <( zenity --title " ITS_ Download Program " --width=560 --text " Copy Paste Download Link " --forms --add-entry " URL: " )

# Download Of Files Location
cd "$(yad --title "Change Directory To Download Destination" --file-selection --directory)"

# Start Program Here
time youtube-dl --ignore-config --hls-prefer-native --add-metadata -i -c --yes-playlist --external-downloader aria2c "$URL" | pv -tpeba -s 500M
ding