$ perl -wle 'print \&CORE::GLOBAL::sleep' CODE(0x224fcb8) $ perl -wle 'print \&CORE::GLOBAL::hubbabubba' CODE(0x1d4acb8) $ perl -wle 'print \&hubbabubba' CODE(0x255bcb8) $ perl -wle '&CORE::GLOBAL::sleep(1)' Undefined subroutine &CORE::GLOBAL::sleep called at -e line 1. $ perl -wle '&CORE::GLOBAL::hubbabubba(1)' Undefined subroutine &CORE::GLOBAL::hubbabubba called at -e line 1. $ perl -wle '&hubbabubba(1)' Undefined subroutine &main::hubbabubba called at -e line 1.