Convert an animated video to gif from http://chrismessina.me/b/13913393/mov-to-gif

vidtogif.sh

# Convert an animated video to gif
# Works best for videos with low color palettes like Dribbble shots
#
# @param $1 - video file name like `animation.mov`
# @param @optional $2 - resize parameter as widthxheight like `400x300`
#
# Example: vidtogif animation.mov 400x300
# Requirements: ffmpeg and gifsicle. Can be downloaded via homebrew
#
# http://chrismessina.me/b/13913393/mov-to-gif

function vidtogif() {
    if [ -n "$1" ]
        then
            mkdir pngs gifs
            ffmpeg -i "$1" -r 10 pngs/frame_%04d.png
            sips -s format gif pngs/*.png --out gifs/
            cd gifs
            if [ -z "$2" ]
                then
                    gifsicle *.gif --optimize=3 --delay=3 --loopcount > ../animation.gif
                else
                    gifsicle *.gif --optimize=3 --delay=3 --loopcount --resize "$2" > ../animation.gif
            fi
            cd ..
            rm -rf pngs gifs
    else
        echo "Use video file as first parameter"
    fi
}