topic Re: Shell in Operating System - Linux

Shell

Indrajit Bhagat — Sat, 05 Aug 2006 08:06:25 GMT

HI ALL,
WHAT ARE SHELL VARIABLES

Re: Shell

James R. Ferguson — Sat, 05 Aug 2006 08:39:34 GMT

Hi:

Strictly speaking, "shell variables" are memory storage areas. That is, the variable or parameter is available only to the shell in which it is declared. Starting a subshell or another process does not inherit the variable. The variable is a 'local' one.

"Environmental" variables are 'global' variables. That is, they are visible by your current shell and any process started by it. The shell PATH, PS1, IFS, and HOME variables are examples of environmental ones.

"Shell variables" would also include the $0, $1...$n positional parameters, representing your program name and the arguments passed to it, respectively.

Shell variables include the $? which is the return value from the last command run; $# which is the number of positional parameters; and the $! which is the pid of the last background process.

Regards!

...JRF...

Re: Shell

James R. Ferguson — Sat, 05 Aug 2006 08:59:31 GMT

Hi (again) Indrajit:

By the way, typing in all uppercase letters is considered to be shouting. It is generally regarded as rude. You should reserve its use for an occassional phrase for emphasis only, and then only rarely.

Regards!

...JRF...

Re: Shell

Kodjo Agbenu — Sun, 06 Aug 2006 15:48:02 GMT

Hi,

On a Linux box using standard "bash" shell, simply type "env" to see currently used shell variables.

Good lcuk.
Kodjo

Re: Shell

Atul Gautam — Mon, 07 Aug 2006 06:11:27 GMT

Hey IB,

Apart from using "env", you can also type "set" and you will see a listing of the environment variables that are set for the current session.

--
Atul