resize all media files in directory using linuxserver/ffmpeg

linuxserver-ffmpeg-resize.sh

#!/bin/bash

# usage
# linuxserver-ffmpeg-resize.sh mkv 720
# linuxserver-ffmpeg-resize.sh avi 1080 480

if [ -z "$1" ]; then
    echo "please provide extension! aborting."
    exit
elif [ -z "$2" ]; then
    echo "please provide original resolution! aborting."
    exit
else
    FROM="$2"
    TO="360"
    if [ ! -z "$3" ]; then
        TO="$3"
        echo "the files will be converted into ${TO}p!"
    fi
    for in in *${FROM}p*.$1; do
        echo "encoding ${TO}p of $in ..."
        OUT=$(echo "$in" | sed -e "s/${FROM}p/${TO}p/g")
        docker run --rm -it \
            -v "$(pwd):/config" \
            linuxserver/ffmpeg \
            -hide_banner -loglevel error -stats \
            -i "/config/$in" \
            -vf scale="-2:$TO" \
            -y "/config/$OUT"
    done
fi