use warnings; use subs 'die'; #our own print, but it doesn't override the built-in sub print { CORE::print scalar(localtime),": "; CORE::print(@_); } #our own die, will override the built-in sub die { print "goodbye cruel world\n";} #calls our custom print #notice you have to use &print() notation &print( "hello world\n"); #calls built in print print "goodbye\n"; #calls our overriden die die "hello";