Do you know what is ascii arts ? Have you ever seen it ?
ASCII arts are the arts that show up on the commandline while we login to linux server using ssh clients such as putty. A Sample ASCII art is given below.
It is very easy to create an art like this. There are a lot of online ASCII art generators. We just need to enter the text and choose the required styling. The tool will automatically create it for us. Some of the links are given below.
http://www.network-science.de/ascii/
http://patorjk.com/software/taag/#p=display&f=Graffiti&t=Type%20Something%20
Copy the ASCII art from this tool and paste it in the following file of your CentOS/RHEL machines.
/etc/motd
Save the file. Logout from the system and login again. You will be able to see the ASCII art on login. You can even use this ascii art in your shell scripts, programs etc.