Re:The Unix `Who` Command
by forgotpwd16 on Thursday September 03, 2020 @12:22PM
(#24365624)
Source for the mentioned script: https://github.com/0intro/plan9/blob/master/rc/bin/who.
Also, other utilities implemented as scripts are fshalt (P9's shutdown), kill, lookman (P9's apropos), uptime and whois.
Does anybody know why there are line breaks in the sed command?
Re:The Unix `Who` Command
by forgotpwd16 on Thursday September 03, 2020 @01:40PM
(#24366506)
It runs multiple expressions. That is
sed '/pattern1/d
pattern2/d'
sed '/pattern1/d; /pattern2/d'
sed -e '/pattern1/d' -e '/pattern2/d'
Thank you! This is exactly the kind of reply I was hoping for.
Is /proc as portable as `ps`?
There's a long explanation when it comes to ps, but the very short answer is twofold:
* Don't parse the output of ps, unless it is my ps command (or plan 9's one, as here). See https://unix.stackexchange.com/a/593198/5132 and https://unix.stackexchange.com/a/578816/5132 , and their further reading, especially Greg Wooledge's article.
* /proc is as portable as ps, but that doesn't really amount to much because neither is really portable at all. Pretty much every operating system's /proc is different; and no implementation of the ps command fully conforms to even the limited subset laid out in the Single Unix Specification.
I see some comments here citing a lack of options, most of which appear to have nothing to do with who is logged into the machine.