Even though there are GUI tools available for doing almost anything under GNU/Linux these days, knowing your way around the command-line can always come in handy.
But unlike with GUI programs, when using a command-line based one, first you have to know its exact name, and then you will have to read its manual (the ‘man page’) as it lists how to use that program, including its other available ‘arguments’ or command-line options etc.
Now both of those things can be achieved using the command-line itself, but if you are new to GNU/Linux, or, even if you are an average user like myself, a GUI tool like ‘Mangui’ will still come in quite handy.
Below are its main feature …
*. Search & read manpages (including viewing them in ‘info’ format).
*. Lists all the available commands.
*. It gives you access to few commonly used commands for finding various informations about command-line programs (‘LOCATE’ command that you can use to search and find things -- with few variations, ‘HELP’, ‘WHATIS’, ‘WHEREIS’ & ‘VERSION’).
‘Mangui’ has built in ‘DEB’ packages and I ran it successfully in Ubuntu 12.10.
If interested, then please visit this ‘Sourceforge’ page for downloading it. Good luck.