This is a great article and people quoting modern manual pages miss the point. The point is that the meaning of su(8) changed and that is conveyed through an nice anecdote where the author discovers exactly how it changed.
In the research version of Tenth Edition Unix, su(8) is described as:
su, setlog -- substitute userid temporarily, become super user
Which is an interesting intermediate step from today's (or rather 2.9BSD's)
su -- substitute user identity
found in BSD derivatives.
Btw, the Tenth Edition manual was written mostly by Douglas McIlroy, inventor of pipes. Even if the 1127 group imported outside code for the VAX versions of research Unix (v8-10), they liked a particular kind of documentation, which the imported code lacked, so they wrote their own. Dare I say the style of research Unix manuals closely matches the style of Go documentation today (unremarkable, considering the pedigree).
This comment has it correct. For those of you on a Mac (and I specifically mention a Mac, due to its BSD userland utilities), you can see that this is still defined this way today: type `man su` and you'll see:
In the research version of Tenth Edition Unix, su(8) is described as:
Which is an interesting intermediate step from today's (or rather 2.9BSD's) found in BSD derivatives.Btw, the Tenth Edition manual was written mostly by Douglas McIlroy, inventor of pipes. Even if the 1127 group imported outside code for the VAX versions of research Unix (v8-10), they liked a particular kind of documentation, which the imported code lacked, so they wrote their own. Dare I say the style of research Unix manuals closely matches the style of Go documentation today (unremarkable, considering the pedigree).