It's not too difficult... you just need split and a regex check. Something like the following is untested but conceptually fairly sound: 
while (<INPUT>) {
    chomp;
    my ($var, $value) = split(/\s*=\s+/, $_, 2);
    if ($value =~ s/^\$(\w+)//) {
#        $value .= $env_var{$1} || '';
        $value = $env_var{$1} . $value;
    }
    $env_var{$var} = $value;
}

[download]
You could make that shorter, but you could also add better checking to make it better. Jellybean actually does this in Jellybean::Config, so I know I've written it correctly at least once before.

Update: Don't work and post. Fastolfe is correct, and I've updated my code to work.

In reply to Re: Parsing variables from login scripts by chromatic
in thread Parsing variables from login scripts by eLore

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