Yeah, there are many ways to put stuff in @INC... As ikegami said, environment variables are the first thing to look at (check perl -V). If there is nothing suspicious there, check your ~/.bashrc and/or other files that are executed at shell startup (perhaps your perl command is an alias to perl -I/home/autumn/perl5/lib/perl5 or something). Then I recall there is also sitecustomize.pl... and, of course, any Perl code can just unshift things into @INC.