Another fun related one: If your username is Tyler and you run shutdown, instead of the usual message it will say "Oh, good morning Mr. Tyler, going down?"
Discovered this in college when I was shoulder surfing a coworker who always used the username Tyler. When he typed shutdown I called it out, and he said, "wait, it doesn't do that for you? I always assumed it said that for everyone and just replaced the username!".
(For those of you too young to know, it's a reference to an Aerosmith song)
One very important section number is 5 - it's for file formats. So if you forget the crontab format, you need to invoke man 5 crontab to read about it.
Remarkable that no one yet here, including the article author, reports the true origin of these section numbers: they identified (depending on section size, one or a group of) physical binders in the series published by AT&T to document System V UNIX, and when you got an update to your system software, it came with a package of new manual pages which you would physically install in the binders to replace the now-superseded older versions. Everything you hate about man pages is in consequence of that origin, and of the corollary that the online version was never designed to be authoritative.
I have one of those physical binders, a volume of Section 3 for an AT&T 3B2, in the software section of my library downstairs. A beautiful artifact in every respect, of the level of quality you would imagine in the manual for a machine that cost $15,000 in the 80s.
My favorite piece of man trivia is from the source of the tunefs BSD man page, which contains:
.\" Take this out and a Unix Daemon will dog your steps from now until
.\" the time_t's wrap around.
.Pp
You can tune a file system, but you cannot tune a fish.
Interestingly, the section doesn't actually have to start with a number. TCL man pages use the 'n' section and 'man' resolves them just fine despite the ambiguity. Conversely, manpage names can also start with numbers, although this is rare (I found only one such example: man 30-systemd-environment-d-generator)
Note that this is contrary to the convention used in the Erlang community, where the number is used to disambiguate function definitions with different parameter counts, e.g. in https://www.erlang.org/docs/18/man/supervisor.html we see definitions of start_link/2 and start_link/3.
It is a stylistic convention to always add this number to any reference to a function, even if there is only one definition.
84 comments
(discussed at https://news.ycombinator.com/item?id=27994194)
Discovered this in college when I was shoulder surfing a coworker who always used the username Tyler. When he typed shutdown I called it out, and he said, "wait, it doesn't do that for you? I always assumed it said that for everyone and just replaced the username!".
(For those of you too young to know, it's a reference to an Aerosmith song)
Haha! Adequate amount of fun was provided, please resume regular man activities.
> (... less common section numbers)
One very important section number is 5 - it's for file formats. So if you forget the crontab format, you need to invoke
man 5 crontabto read about it.I have one of those physical binders, a volume of Section 3 for an AT&T 3B2, in the software section of my library downstairs. A beautiful artifact in every respect, of the level of quality you would imagine in the manual for a machine that cost $15,000 in the 80s.
https://pubs.opengroup.org/onlinepubs/9799919799/idx/xcu.htm...
These would all be in section 1, if I am correct.
Run
apropos . | grep "(3)"; you'll be surprised how many libraries come with man pages for their functions (e.g; curl).Now I wonder if there are any IDEs that can automatically dial into these man pages and pull up documentation for functions?
man manStep 2: Feel the urge to write an article about that
start_link/2andstart_link/3.It is a stylistic convention to always add this number to any reference to a function, even if there is only one definition.
Perhaps the modern version of "man" should be a program you can talk to.