[xenophonf]

Simon writes:

> To [switch users], /bin/login would need to be setuid, and it certainly isn’t on Linux... _Perhaps_ Solaris (or SolarOS) is different?

The login command is indeed setuid root on SunOS 4, to which the movie pays homage, as its documented behavior is "to [permanently] change from one userID to another". The su command explicitly means "temporarily switch to a new user ID".

Here are copies of the SunOS 4 manual pages, if you're curious:

http://www.typewritten.org/Manual/Sun/SunOS/4.0.2/man1/login...

http://www.typewritten.org/Manual/Sun/SunOS/4.0.2/man1/su.ht...

And here's a link to the relevant bits of the SunOS 4.1.3 source code:

https://github.com/Arquivotheca/SunOS-4.1.3/blob/2e8a93c3946...