=over =item $# X<$#> C<$#> was a variable that could be used to format printed numbers. After a deprecation cycle, its magic was removed in Perl v5.10.0 and using it now triggers a warning: C<$# is no longer supported>. This is not the sigil you use in front of an array name to get the last index, like C<$#array>. That's still how you get the last index of an array in Perl. The two have nothing to do with each other. Deprecated in Perl 5. Removed in Perl v5.10.0. =back