I am curious to understand the original 'C' source code for shell (Command Line Interpreter) of Linux. I tried going in to /usr/src/linux. But, I couldn't figure out which one to seacrh for. Can some one help me how and where exactly I can walk through the source code for understanding various components (not only the kernel) of linux operating system. Thanks in advance.

Source for Bash (which is probably your shell) is availiable from GNU http://www.gnu.org/directory/bash.html Kernel == kernel.org /usr/src/linux is where the kernel source is GENERALLY stored. What do you want to understand about it??? The whole thing is like 30 megs as a tar.bz2... That's a lot of code. The directory names should be pretty revealing... I think there's an 'fs' directory (file systems). they're all labeled like that. Look around. Explore. "Sometimes, the quest for knowldedge is more important than its possesion." Or something like that. I think Einstien said that. Could be someone else, though. I sincerly doubt you'll find any sort of tutorial on bash's source code. Or even the kernel for that matter. If you can read C, you'll be able to figure it out. If not, learn C ;)