The connec_sh script morses the IP + "connected" when a user connects to filebitchs proftpd server. 
It will hopefully drive someone crazy.

To make it run you need to add some lines to your proftpd config.
I decided not to let Krebs do this as I didn't want to break your FTP Server (I know FTP is broken by default).
The 5 necessary lines are:
ExtendedLog     /var/log/proftpd/ftp_auth.log AUTH auth
<IfModule mod_exec.c>
    ExecEngine on
    ExecOnConnect "/krebs/filebitch/connect_narf.pl"
</IfModule>