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Full Discussion: $PWD vs `pwd`
Top Forums UNIX for Dummies Questions & Answers $PWD vs `pwd` Post 302590656 by venkatareddy on Tuesday 17th of January 2012 05:39:19 AM
Old 01-17-2012
Hi,
Both are same w.r.t functionality , This variable points to the current directory

But $PWD is an environmental variable which can be used to set to a particular session/shell /script

Working principles of environment variables

A few simple principles govern how environment variables BY INSTALLING, achieve their effect.

Local to process

Environment variables are local to the process in which they were set. That means if we open two terminal windows (Two different processes running shell) and change value of environment variable in one window, that change will not be seen by other window.

Inheritance
When a child process is created, it inherits all the environment variables and their values from the parent process. Usually, when a program calls another program, it first creates a child process by forking, then the child adjusts the environment as needed and lastly the child replaces itself with the program to be called. This procedure gives the calling program control over the environment of the called program.

Case sensitive
In Unix and Unix-like systems the names of environment variables are case sensitive.
Persistence
Environment variables persistence can be session-wide or system-wide.

thanks,
venkat
 

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set(1F) 							   FMLI Commands							   set(1F)

NAME
set, unset - set and unset local or global environment variables SYNOPSIS
set [-l variable [=value]] ... set [-e variable [=value]] ... set [-ffile variable [=value]]... ... unset -l variable... unset -f file variable... DESCRIPTION
The set command sets variable in the environment, or adds variable=value to file. If variable is not equated it to a value, set expects the value to be on stdin. The unset command removes variable. Note that the FMLI predefined, read-only variables (such as ARG1), may not be set or unset. Note that at least one of the above options must be used for each variable being set or unset. If you set a variable with the -ffilename option, you must thereafter include filename in references to that variable. For example, ${(file)VARIABLE}. FMLI inherits the UNIX environment when invoked. OPTIONS
-l Sets or unsets the specified variable in the local environment. Variables set with -l will not be inherited by processes invoked from FMLI. -e Sets the specified variable in the UNIX environment. Variables set with -e will be inherited by any processes started from FMLI. Note that these variables cannot be unset. -ffile Sets or unsets the specified variable in the global environment. The argument file is the name, or pathname, of a file containing lines of the form variable=value. file will be created if it does not already exist. Note that no space intervenes between -f and file. EXAMPLES
Example 1 A sample output of set command. Storing a selection made in a menu: name=Selection 2 action=`set -l SELECTION=2`close NOTES
Variables set to be available to the UNIX environment (those set using the -e option) can only be set for the current fmli process and the processes it calls. When using the -f option, unless file is unique to the process, other users of FMLI on the same machine will be able to expand these vari- ables, depending on the read/write permissions on file. A variable set in one frame may be referenced or unset in any other frame. This includes local variables. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
env(1), sh(1), attributes(5) SunOS 5.11 5 Jul 1990 set(1F)
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