$ echo "a.pl did not return a true value at ./require.plx line 7." | splain a.pl did not return a true value at ./require.plx line 7 (#1) (F) A required (or used) file must return a true value to indicate that it compiled correctly and ran its initialization code correctly. It's traditional to end such a file with a "1;", though any true value would do. See perlfunc/require.