ftptop(1) on Linux
The text 5a509eed3be9, as Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
display running status on proftpd server connections
Flags it lists
-
-A -
-D -
-I -
-S -
-U -
-V -
-a -
-d -
-f -
-i