to add a bit more, this is a clash of unix expectations on plan 9 that people hit all the time when they start.
if you're used to /etc/passwd, then you'll assume that /adm/users is the same thing, different name. A single file, in a directory, which names all possible users of a system, and hence, all identities on the file system. To add users or groups, you might assume you just change /adm/users, and that's where you see things are different -- as you're seeing. But consider: would you assume that a file server at u. calgary and a file server in san diego have the same set of users? On Plan 9, you can mount them both, and any other file server, at any time. There's no way that a single file on a single FS can describe the users for all those file servers, and that's part of why what you are doing is not working. To extend /adm/users, you need to talk to the file server it was derived from. I always felt that the nice thing about having Plan 9 on a single machine is that people don't have to set up the little network of auth, fs, cpu, and terminal; the downside is that having it on a single machine leads people to think it's another unix-like system (I see this all the time). On Thu, Aug 20, 2026 at 11:33 PM <[email protected]> wrote: > File metadata is managed by your file server, so you need to add your > groups to the file server first; simply editing /adm/users doesn't > necessarily update the user table. See fs(8) for specifics. > > > 2026年8月21日 6:48:15 JST、[email protected] より: > >> Greetings. This -should- be trivial. >> >> I am going through "Introduction to Operating Systems Abstractions", >> which you can find easy online. On page 68, section 3.5, it gives a code >> to change the group of a file. The code works, in a manner of speaking. >> If I try to change the group of the file to something "legal", it works. >> The problem is, the group it changes the file to, "planb", is not a group >> on my system. I'm using 9legacy on qemu. >> >> The internet has helped me find /adm/users , and I have used it to add >> "planb". [planb:planb::glenda] However, having done that, saved, and >> verified that the new group is there, using cat, the program still fails to >> work. "unknown gid". >> >> more specifically: >> >> chgrp: wstat: wstat -- unknown gid >> >> Nothing critical here, just trying to be systematic in learning the new >> system. Help appreciated. >> > *9fans <https://9fans.topicbox.com/latest>* / 9fans / see discussions > <https://9fans.topicbox.com/groups/9fans> + participants > <https://9fans.topicbox.com/groups/9fans/members> + delivery options > <https://9fans.topicbox.com/groups/9fans/subscription> Permalink > <https://9fans.topicbox.com/groups/9fans/T9150ebcacf826b8c-M3b6f63f8a0267719e324cdb6> > ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/T9150ebcacf826b8c-M285d9fd890563d3714b2745a Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
