or download this
$ perl -MIO::Socket::INET -E'
system "ls -lF /proc/$$/fd/";
...
lrwx------ 1 eric users 64 Feb 14 15:22 2 -> /dev/pts/7
lr-x------ 1 eric users 64 Feb 14 15:22 3 -> socket:[2358143]
lr-x------ 1 eric users 64 Feb 14 15:22 4 -> pipe:[2358144]