Convert video AVI/MPEG/MP4 to a Gif animation on Linux

How to convert a video file to an animated GIF on Linux:

1. Install required software:
   apt-get install ffmpeg gifsicle imagemagick:
2. Convert the video file to a series of small images:
   mkdir /tmp/gif/
   ffmpeg -i YOURVIDEOFILE.mp4 -r 10 -s 711×400 /tmp/gif/out%04d.gif 
3. Combine these images together into a GIF animation:
   gifsicle –delay=10 –loop /tmp/gif/*.gif > animation.gif
4. Optimise the GIF animation so the file size is smaller:
   convert -layers Optimize animation.gif animation_optimized.gif