Perl/Useful hacks

Rename the contents of directory
foreach my $file (glob "*.old") { my $newfile = $file; $newfile =~ s/\.old$/.new/; if (-e $newfile) { warn "can't rename $file to $newfile: $newfile exists\n"; } elsif (rename $file, $newfile) { ## success, do nothing } else { warn "rename $file to $newfile failed: $!\n"; } } Thought there is much faster way to do this in bash i bet (link from here if you know of one)
 * How to rename everything that ends with ".old " to the same name with ".new". Here's how to do it in Perl nicely: