Read up here - caller

sub whoami  { (caller(1))[3] };  #returns name of the sub that called
                                 # this sub
sub whowasi { (caller(2))[3] };  #returns name of the parent of the 
                                 # sub that called this sub
do_calc (1,2,3);

sub do_calc
{
   print "In subroutine: do_calc()\n";
   print "I am: ",whoami,"\n\n";
   do_sub_calc();
}

sub do_sub_calc
{
   print "In subroutine do_sub_calc()\n";
   print "I am: ", whoami(),"\n";
   print "I was called by: ", whowasi(),"\n";
}

__END__
prints:
In subroutine: do_calc()
I am: main::do_calc

In subroutine do_sub_calc()
I am: main::do_sub_calc
I was called by: main::do_calc
[download]

Better to use Carp for tracing a call stack than caller.

If you only want one layer back, use carp(). And if you want the whole call stack, use cluck(). But if you want anything in between, you need to build it yourself with caller().

- doug

perldoc -f caller