@liebook it is achieved using a program called glitchcat (just like cat, but with glitch animations), I found it in the AUR as glitchcat-git.

You can also find it on github: https://github.com/kuviman/glitchcat

After the install I just included this at the end of my .zshrc file (it could be in .bashrc instead y you use bash):

glitchcat -a 100 -d 600 -f 400 -g 100 -m HomoGlyphs ~/Imágenes/ASCII/lain/lain$(azar 1 7)

The “azar” function basically takes a random number between an interval, which I use to pic a random ASCII art text in a folder. It is defined as follows inside .zshrc:

function azar(){    minimo=$1    maximo=$2    diferencia=maximo-minimo+1    echo $(((RANDOM % diferencia) + minimo))}