Re: A number of things wrong with this reply
A lot of University mainframes in the 70's and 80's ran the Michigan Terminal System (MTS). This was a time sharing O/s from University of Michigan. It has several advantages over TSO or VM/CMS from IBM. First it could run a lot of cheap terminals, rather than the IBM 3270 consoles; and secondly is was considerably cheaper and came with source code.
This did NOT use REXX. But it did have a shell script of sorts, but I agree not Python.
It did however have a feature that could send a message to the operators console. It was meant for things like "Please load tape VT12345 on Tape Drive 4 with ring in".
This was used by my University colleagues to write a small assemble program that could send ASCII art messages to the OPERATOR. It was oh so funny when someone sent BIG BROTHER IS WATCHING to the operator in the remote data centre.
It was somewhat less funny when the operators decided it was a message that management were watching their every activity and, as good union members, all walked out, shutting the mainframe down in the process.
Even less fun was the poor undergraduates who authored the hack having to grovel to the operators.