$perl
use IO::Socket;
print "Hello" . "\n";
Hello

##</code><code>##

$perl
use IO::socket;
print "Hello" . "\n";
Hello

##</code><code>##

$perldoc -l IO::Socket;
/usr/local/ActivePerl-5.10/lib/IO/Socket.pm

$perldoc -l IO::socket;
/usr/local/ActivePerl-5.10/lib/IO/socket.pm

##</code><code>##

$ls -l /usr/local/ActivePerl-5.10/lib/IO/
total 216
drwxr-xr-x  13 root  admin    442 Sep 24 15:51 Compress
-r--r--r--   1 root  admin   5372 Aug 24 17:00 Dir.pm
-r--r--r--   1 root  admin   4907 Aug 24 17:00 File.pm
-r--r--r--   1 root  admin  16421 Aug 24 17:00 Handle.pm
-r--r--r--   1 root  admin   5473 Aug 24 17:00 Pipe.pm
-r--r--r--   1 root  admin   4554 Aug 24 17:00 Poll.pm
-r--r--r--   1 root  admin   2935 Aug 24 17:00 Seekable.pm
-r--r--r--   1 root  admin   8021 Aug 24 17:00 Select.pm
drwxr-xr-x   4 root  admin    136 Sep 24 15:51 Socket
-r--r--r--   1 root  admin  13572 Sep 24 17:06 Socket.pm
-r--r--r--   1 root  admin  11461 Dec  5  2005 String.pm
drwxr-xr-x  11 root  admin    374 Sep 24 15:51 Uncompress
-r--r--r--   1 root  admin  15015 Jul 14 17:30 Zlib.pm