First to asciinema : free and open source solution for recording terminal sessions and sharing them on the web.
Second to agg : agg is a command-line tool for generating animated GIF files from asciicast v2 files produced by asciinema terminal recorder.

Build

$ docker build . -t term2gif-run -f Dockerfile.asciinema

$ docker build . -t term2gif-gif -f Dockerfile.agg

images

term2gif-gif & term2gif-run are avaible on docker.tuxme.net if you have an account

Script

👾┌─[:(]─[22:33:01]─[guillaume@virgile]─[~/data/git/term2gif]
└──> ./term2gif 
./term2gif [Path To File]
Ex : ./term2gif /home/guillaume/File.cast
.cast extension is mandatory

Exemple

👽┌─[22:33:02]─[guillaume@virgile]─[~/data/git/term2gif]
└──> ./term2gif ${HOME}/MyFirstGif.cast
asciinema: recording asciicast to /data/MyFirstGif.cast
asciinema: press <ctrl-d> or type "exit" when you're done
root@MyFirstGif:~# echo Now i am recording
Now i am recording
root@MyFirstGif:~# echo ciao
ciao
root@MyFirstGif:~# exit
exit
asciinema: recording finished
asciinema: asciicast saved to /data/MyFirstGif.cast
49 / 49 [=====================================================================================] 100.00 % 14.00/s 
##################################################
cast file : /home/guillaume/MyFirstGif.cast
cast file : /home/guillaume/MyFirstGif.gif
##################################################

Exmple Gif

Here is the prinscreen of all the action

Here is the result