Linux secrets

I will be posting here Linux secrets commands that are not very well known


Space Invaders

OpenOffice.org 2.0/OpenOffice.org 3.2.1 
there's an entire game hidden in OpenOffice.org Calc. Open a new worksheet, and in any cell, type in the formula:
=game("StarWars")

and press Enter. You should see a Space Invaders-style arcade game.

Signature in ASCII graphics 

A sample output. ( press CTRL-D after you type the message)

$ boxes -d peek
STELIOS AGAPIOU
check my Blog
myhomelab.blogspot.com

 $ sudo apt-get install boxes

$ boxes -help
boxes - draws any kind of box around your text (and removes it)
        (c) Thomas Jensen <tsjensen@stud.informatik.uni-erlangen.de>
        Web page: http://home.pages.de/~jensen/boxes/
Usage:  boxes [options] [infile [outfile]]
        -a fmt   alignment/positioning of text inside box [default: hlvt]
        -d name  select box design [default: first one in file]
        -f file  use only file as configuration file
        -h       print usage information
        -i mode  indentation mode [default: box]
        -k bool  kill leading/trailing blank lines on removal or not
        -l       list available box designs w/ samples
        -p fmt   padding [default: none]
        -r       remove box from input
        -s wxh   specify box size (width w and/or height h)
        -t uint  set tab stop distance [default: 8]
        -v       print version information

Use the command below to see all the available boxes

$ boxes -l