Re^5: replicating the command 'unset LIBPATH' in perl

[Anonymous Monk]

This should work

#!/usr/bin/perl --
BEGIN {
    unless( $ENV{ +__FILE__ } eq __FILE__ ){
        delete $ENV{LIBPATH};
        $ENV{ +__FILE__ } = __FILE__;
        exec $^X, __FILE__, @ARGV; # relaunch without LIBPATH
    }
}
...

[JavaFan]

That can be simplified to:

BEGIN {
    if (exists $ENV{LIBPATH}) {
        delete $ENV{LIBPATH};
        exec $^X, __FILE__, @ARGV;
    }
}

[viffer]

Thanks gents - I now feel like the beginner I am!

But....what is __FILE__?

[Anonymous Monk]

Its not a secret :) __FILE__ site:perldoc.perl.org The special literals __FILE__, __LINE__, and __PACKAGE__ represent the current filename, line number, and package name at that point in your program.

$ perl -e"die __FILE__"
-e at -e line 1.

$ echo die __FILE__ > thefileis

$ perl -e"die __FILE__"
-e at -e line 1.

$ echo die __FILE__ > thefileis

$ perl thefileis
thefileis at thefileis line 1.

$ perl D:\thefileis
D:\thefileis at D:\thefileis line 1.

$