$ perl -d ./aliasing1.pl

Loading DB routines from perl5db.pl version 1.28
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

main::(./aliasing1.pl:5):    socket(SOCK, PF_INET, SOCK_STREAM, getprotobyname("tcp")) or die "socket: $!";
  DB<1> c
before aliasing: sock=9, STDIN=0, STDOUT=1
after aliasing:  sock=9, STDIN=0, STDOUT=1
enter something:
foo
you typed: foo
^C
IO::Handle::DESTROY(/usr/local/perl-5.8.8/lib/5.8.8/i686-linux/IO/Handle.pm:328):
328:    sub DESTROY {}
  DB<1> q
$