Add freebsd-tips fortune about sysctl kern.tty_info_kstacks

[grembo]

Summary

Following this discussion on -current,
https://lists.freebsd.org/archives/freebsd-current/2021-May/169405.html
add a little something to fortune.

Update: Mail archive link changed: https://lists.freebsd.org/archives/freebsd-current/2021-May/000021.html

Test Plan

$ cd usr.bin/fortune/datfiles
$ make
$ while true; do fortune freebsd-tips | grep -A4 stack && break; done

[grembo]

Adding docs, as this might be more appropriate(?)

[ceri]

That sysctl is 2 by default, at least on -CURRENT.
Do we care that this is wrong on CURRENT (I don't think I do) ?

[grembo]

In D30388#689933, @ceri wrote:

That sysctl is 2 by default, at least on -CURRENT.
Do we care that this is wrong on CURRENT (I don't think I do) ?

I think it's 1 by default on CURRENT at the moment (https://cgit.freebsd.org/src/commit/sys/kern/tty_info.c?id=e94fdc38331157d7d0bc888a14279f03639e09a2).

@ceri Alternative wording:

You can control kernel stack(9) traces on ^T (tty info) by setting
kern.tty_info_kstacks to 0 (off), 1 (on), or 2 (verbose), e.g.:

# sysctl kern.tty_info_kstacks=2

		-- Michael Gmelin <[e-mail]>
%

[ceri]

In D30388#689940, @grembo wrote:

@ceri Alternative wording:

You can control kernel stack(9) traces on ^T (tty info) by setting
kern.tty_info_kstacks to 0 (off), 1 (on), or 2 (verbose), e.g.:

        sysctl kern.tty_info_kstacks=2

		-- Michael Gmelin <[e-mail]>
%

Yeah, this is nicer and more futureproof, ta.

[bcr]

Cool, I like this.

[grembo]

Make wording more general, use root prompt ("#").

[ceri]

gtg

[grembo]

@ceri Thanks for taking the time to review.