One quick and dirty way to do this is to declare some variables in the script, eval require the file, if eval succeeds equate the script var names with the var names in the required file.

use strict;

use vars qw($filevar1 $filevar2 $filevar3);

my($scriptvar1,$scriptvar2,$scriptvar3,$required) = 0;

my$file = 'somefile';

if(-e $file){
     if(eval "require '$file'"){
          $scriptvar1 = $filevar1; 
          $scriptvar2 = $filevar2; 
          $scriptvar3 = $filevar3;
          $required = 1;
          }
     }
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Those my variables can be included in the use vars statement instead (but not vice-versa).