I think ls is most common or first command that linux user or admins used to type after login on Linux terminal but sometime we type sl instead of ls, was it happened with you…? Well it does happened with me many times and what then, unix/Linux will tell command not found. But i have one alternative, you must be thinking making alias of sl for ls command, well its a Good idea.
But this time i am thinking in another direction where we can make it more fascinating for Linux/unix Users. So we have sl command that will display animations Moving train on Linux terminal.

SetUP

For this Setup we are using Ubuntu machine, 16.04.3 LTS updated as of now Jan 2018.

root@jarvis:~# lsb_release -d
Description:	Ubuntu 16.04.3 LTS

root@jarvis:~# uname  -rm
4.4.0-109-generic x86_64

Installation

For installation on Ubuntu machine we just use apt-get command. In case of Linux we can install through rpm or yum command

# apt-get install sl

Once you have installed it Run sl command will show you animations Moving train on Linux terminal like below