%ENV E.g.: 
print "Path = ", $ENV{PATH}, "\n";
$ENV{PATH} .= ";c:\temp";          # add c:\temp to it

[download]
You may be interested in the perlvar documentation.

Not sure how it works under Windows, but under Unix these changes are not global and only survive for the life of your script and its children.

In reply to Re: How to access system environment variables? by Fastolfe
in thread How to access system environment variables? by Anonymous Monk

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