Sometimes all you need is a kind greeting, even if it is from a creepy robotic voice!

Make the bash shell greet you by writing a script that will run when you start a bash shell and that will print a greeting to you (current user).

It should say something like "Hello john, Good Morning!".

Depending on the time of the day, the greeting should vary. (eg:- "Good afternoon!")

Using a simple "text to speech" method available in your system ('spd-say' in ubuntu, 'say' in OS X etc.) make bash actually speak out those greetings. If such a method is not available in your system you can checkout espeak (http://espeak.sourceforge.net/).

Useful links

http://man7.org/linux/man-pages/man1/date.1.html
http://man7.org/linux/man-pages/man1/whoami.1.html