Shell script that converts a video to a gif file using ffmpeg and convert commands

video2gif.sh

#!/bin/sh

if [ $# -eq 0 ]; then
	echo "video2gif.sh [INPUT] [HEIGHT] [START] [LENGTH]"
	exit
fi

INPUT=$1
HEIGHT=$2
INIT=$3
LENGTH=$4

ffmpeg -i $INPUT -vf scale=-1:$HEIGHT -ss $INIT -t $LENGTH -r 14 -f image2pipe -vcodec ppm - | convert -delay 7 -loop 0 -dither None -colors 80 -fuzz "40%" - gif:- | convert -layers Optimize - $INPUT-optimized.gif