How to set an environment variable in perl so that it's visible to subsequent processes?

[anzalone]

I want to set an environment variable from within the perl script so that it's visible to other subsequent processes, like what export var=xyz does in unix shells.
Something like $ENV{'var'} = 'xyz' has effect only for the current process and any children it spawns.

Originally posted as a Categorized Question.

[jdporter]

For Unix at least, the short answer is that it can't be done. This is in the Perl FAQ, by the way: I {changed directory, modified my environment} in a perl script. How come the change disappeared when I exited the script? How do I get my changes to be visible?

[anzalone]

On Windows, you can use the Win32::AdminMisc module (by Dave Roth, not on CPAN), which has a function for this, SetEnvVar:

SetEnvVar( $Name, $Value [, $Type [, $Timeout ] ] )

This will set an environment variable $Name to $Value. This function will set the variable (creating it if $Name does not exist).
The new value will be set globally so all applications will be able to use it, unlike setting $ENV{xxx} — which sets the variable for the current process and any children it spawns afterwards.
When this function is called a broadcast to all running applications is made telling them about the variable change. An application may choose to ignore the change if it was programmed to do so.
If $Timeout is specified then the broadcast announcement will be aborted if it takes longer than $Timeout seconds (some applications may be in a hung state so they can not acknowledge the broadcast). If this timeout occurs the variable will still be updated but broadcasting it's change will be aborted.
If $Type is specified it can be one of:

ENV_SYSTEM

Specifies that $Name will be a system environment variable. (default if $Type is not specified)

ENV_USER

Specifies that $Name will be a user environment variable.

This function is the equivalent to setting an environment variable in the control panel's system applet.

NOTE: Your script will not see the new value. For that you should set $ENV{xxx}.

Example:

Win32::AdminMisc::SetEnvVar( "Temp", "$ENV{HOMEDRIVE}$ENV{HOMEPATH}", 
+ENV_USER, 10 );

Returns:

0 if not successful

1 if successful

Win32::AdminMisc also has a DelEnvVar function for deleting environment variables.

[heeru]

How can we do the same for LINUX?

Originally posted as a Categorized Answer.