I'm not good at remembering long commands, so my .bash_profile is littered with things like this. This one converts a movie file into a gif. See https://gist.github.com/dergachev/4627207 for details.

gistfile1.sh

# Convert a movie file to a gif. Crappy quality, only good for short screen cap
# See https://gist.github.com/dergachev/4627207
function gifify {
  if [ -z "$1" ]
  then
    # No parameter passed, show usage
    echo "Usage: gifify filename.mov"
    echo "Resulting gif is stored as out.gif"
  else
    ffmpeg -i $1 -s 600x400 -pix_fmt rgb24 -r 10 -f gif - | gifsicle --optimize=3 --delay=3 > out.gif
  fi
}