$ perl -v
This is perl, v5.6.1 built for i386-linux
$ perl -MExpect -le 'print $Expect::VERSION'
1.15
$ strings `which sftp` | grep sftp-client
@(#)$OpenBSD: sftp-client.c,v 1.33 2002/06/23 09:30:14 deraadt Exp $