shell scripting

Korn SHell - ksh

SHell - sh

Another SHell - ash

Bourne Again SHell - bash

References, Authors, Websites, Blogs

http://www.tldp.org
http://www.funtoo.org/
http://www.distrowatch.org
http://en.wikibooks.org/wiki/Linux

Basics - commands & file structure

LINUX is the 'Operating System Kernel' it was invented by Linus Torvalds.
(It is similar to Unix in many ways)
GNU stands for the recursive acronym GNU's Not Unix.
Richard Stallman is the founder of the GNU movement
The applications run on the Linux kernel make the system useful as a whole. Hence, a system running applications on the GNU kernel is normally referred to as GNU/Linux.
GNU/Linux is mostly FREEWARE as in 'free speech' NOT 'free beer'. Meaning, you can charge for the software but must make the source code available as well as give proper credit to the author of the original source code along with rights of modification to the code and imposing the same liberties.

All the commands listed below will have to be typed in a 'terminal'.
Most commands have lots of options but only a few important ones are listed here. For a detailed listing, please refer to the 'man' pages.

1. ls
2. who
3. whereis
4. whatis
5. info
6. man
7. updatedb
8. logout
9. exit
10. echo
11. cd
12. pwd
13. passwd
14. mkdir
15. touch
16. cat
17. cp
18. mv
19. ln
20. rm
21. rmdir