#########   calling script
#!/usr/bin/perl
use strict;
my $x;
my $file = 'my.conf';
unless (my $return = do $file) {
    warn "couldn't parse $file: $@" if $@;
    warn "couldn't do $file: $!"    unless defined $return;
    warn "couldn't run $file"       unless $return;
}
print "\$x is $x\n";

##########   config script (my.conf)
package main;
$x = 'abcdef';
42;