On Mon, Jun 20, 2022 at 6:23 PM наб <nabijaczleweli@xxxxxxxxxxxxxxxxxx> wrote: > > Hi! > > On Mon, Jun 20, 2022 at 11:55:18AM +0300, Stefan Puiu wrote: > > On Mon, Jun 20, 2022 at 2:40 AM наб <nabijaczleweli@xxxxxxxxxxxxxxxxxx> wrote: > > > > > > Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx> > > > --- > > > man7/environ.7 | 8 ++++++-- > > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > > > diff --git a/man7/environ.7 b/man7/environ.7 > > > index 019c5a25a..24446c709 100644 > > > --- a/man7/environ.7 > > > +++ b/man7/environ.7 > > > @@ -158,8 +158,12 @@ used by > > > to find manual pages, and so on. > > > .TP > > > .B PWD > > > -The current working directory. > > > -Set by some shells. > > > +Absolute path to the current working directory; > > > +required to be partially canonical (no > > > +.I .\& > > > +or > > > +.I ..\& > > > +components). > > > > If any shell decides to ignore that part of the spec, is there > > anything preventing them? > It no longer being a valid shell (if on startup) or providing an invalid > cd built-in (when cding), from the stand-point of conformance to both > the standard and historical shells. My expectation from the Linux manual pages is that they document behavior I'm likely to encounter in the real world on Linux, with various libcs etc. Specs can be misread, misunderstood, ignored, or can be wrong sometimes (see the discussion about fork being required to be async signal safe, for example, the RH page here: https://access.redhat.com/articles/2921161). So if I write software that, say, does getent("PWD"), it's useful to know if there are cases where that might not work. Even if POSIX requires PWD to be set, that's not reassuring when my program crashes. That's why I asked if you checked some shells to see what they do. Also, I see there's already environ.3p for the POSIX version. > > > I would make it clear in the text that this > > is a spec requirement, not a practical guarantee (e.g. "required by > > <spec> to be ..."). > Those are one and the same, that's the point of SUS/POSIX > (and conformance to historical implementations). > Are you aware of one or are you just concern-trolling? I don't know of a shell that doesn't set PWD, but since you said the previous comment ("Some shells set it") was wrong, I assumed you had checked that. I did try bash and busybox sh and they seem to set it, but there are (quite) a few other shells out there. I don't know why you think that my question is some kind of trolling. You can look up my contributions in the mailing list archive. It's been a while since my last patch to the project; nowadays I follow some of the mailing list discussions in my spare time and occasionally chime in on people's patches. I get things wrong sometimes, of course, but your reply is the first one that is defensive (and somewhat rude, I would say). Probably a good indication that I need to find other uses of my (spare) time. > Obviously, pretty much no part of this manual applies to csh > because csh is its own 2BSD brand of insanity (in this case > largely because it predates V7 (3BSD), and, hence, the environment). > csh users understand they use a non-shell, Well, this is the environ.7 man page, mostly useful to programmers AFAICT, who don't have much control over what people use as their shell. If they can set csh as their login shell, why should I assume they won't? People have many reasons to choose the shell they run - distro default, they like some features, speed, company policy, legacy systems... Not sure POSIX compliance is high on that list. Heck, Linux is not fully POSIX-compliant (see https://linuxhint.com/is_linux_posix_compliant/), does that make it a non-OS? Regards, Stefan. > it's not mentioned here because why would it be? > It's not mentioned anywhere else. > > Best, > наб
