#./program.pl 
lib my
Use of uninitialized value in print at ./program.pl line 6.
Use of uninitialized value in print at ./program.pl line 7.
Use of uninitialized value in concatenation (.) or string at ./program.pl line 12.
Use of uninitialized value in concatenation (.) or string at ./program.pl line 12.
our endlib