how can i find commands where it stored?

Programs are usually stored at one of these paths:

If that's what you mean.

First, in a command line, do: echo $PATH.

"$PATH" is a variable that specifies where Linux will look to find most commands. (The which command will tell you "which" program would be run in response to any command.)

Some commands are built-in to the shell: see info bash. ("The shell" is the program that gives you that command prompt in the first place...) For these, the shell does not invoke an external program.

Finally, for security reasons "$PATH" normally does not include the current-directory. You can always run a command by giving its filename explicitly.

The "$PATH" setting for you is particular to you and you can therefore change it any time during your session.

kamal;

Please stop posting these simplistic questions which you could easily find in a Google search. This is going to very quickly erode your credibility here.

which <command>

But typically they're in some standard places. Not that they do you any good if you don't know how to use them.

/bin
/sbin
/usr/bin
/usr/sbin
....

man man

cd /usr/share/doc/
cat * | more

find / -iname '*BOFH*'

tldp.org
linuxdoc.com

freshmeat.net
sourceforge.net