telnet.netkit(1) on Linux
The text 6695f47c4b4d, as Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze), Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
user interface to the TELNET protocol
Flags it lists
-
-4 -
-6 -
-8 -
-E -
-L -
-S -
-a -
-b -
-d -
-e -
-input -
-l -
-n -
-output -
-r