Unix, not Perl

For a change, I am mentioning something about Unix, not Perl.

You may want to set your PS1 in your .bash_profile or .cshrc file as follows:
export PS1='\@:$PWD\$'

\@ displays the time in 12 hours format with AM/PM
$PWD shows the pwd (present working directory)
\$ turns to # if you su to be root

Your prompt will appear like this:
01:03 AM:/home/kasper/HA/reports$

Interview Puzzles with answers

Whether you are taking an interview or giving one, this link is sure to be helpful.