ben@Tyr:/tmp$ echo -e 'sub greet { "Hello, world!\\n" }\n1;' > hello.pl
ben@Tyr:/tmp$ perl -Mhello.pl -we'print greet'
syntax error at -e line 0, near "use hello."
Execution of -e aborted due to compilation errors.
ben@Tyr:/tmp$ perl -Mhello -we'print greet'
Can't locate hello.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.8.8 /usr/local/share/perl/5.8.8 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.8 /usr/share/perl/5.8 /usr/local/lib/site_perl /usr/local/lib/perl/5.8.7 /usr/local/share/perl/5.8.7 .).
BEGIN failed--compilation aborted.