On 01/01/2013 06:49:00 AM, Felix Janda wrote:
On 12/31/12 at 09:50pm, Rob Landley wrote:
> On 12/31/2012 10:39:18 AM, Felix Janda wrote:
> > On 12/30/12 at 05:47pm, Rob Landley wrote:
> > > On 12/30/2012 05:16:41 AM, Felix Janda wrote:
> > > > On 12/30/12 at 04:43am, Rob Landley wrote:
> > > > POSIX contains many surprises. In the section on environment
> > > > variables it
> > > > says that $PWD should be set if "pwd -P" was specified. What
> > happens
> > > > if an
> > > > error happens seems unspecified.
> >
> > Sorry, this is wrong. It has been changed between SUSV4 and SUSV3.
> > Now pwd
> > must not change $PWD. (It would be really nice to have SUSV4 man
> > pages...)
>
> There are susv4 web pages which you can download and pull up with
> "links" or similar if it really bothers you.
Having something like "man 1p pwd" is just too convenient.
> Trying to beat sane behavior out of bash is not a fruitful endeavor:
>
> cd
> mkdir missing
> cd missing
> rmdir ../missing
> pwd -P
> cd ..
> ls
> echo $PWD
>
> I'm not copying that behavior.
Of course, me neither. bash seems still to try to follow the older
version
of POSIX, but its version of "pwd -P" seems to be broken in another
way.
Do I understand correctly that in the case that pwd (as a builtin of
toysh)
can't determine the path of the current working directory with
getcwd() it
should fall back to printing $PWD?
1) The default value is -L, and it only looks at $PWD in -L mode. If
you say pwd -P with no cwd, it should fail.
2) If $PWD is set to a value that the shell wouldn't set it to, it's
discarded and we fall back to -P. Specifically, if it's not an absolute
path, or if it contains . or .. components, it is considered invalid.
3) If $PWD does not point to the current directory, fall back to -P.
What I did was disable #3 in the case where cwd doesn't exist. So the
new rule #3 is:
3) If cwd exists and $PWD doesn't point to it, fall back to -P.
BTW, in the case that one has deleted and recreated one's current
working
directory one could also use "cd ." to get to the new directory.
Good to know. (This means the shell is special casing "." as well as
"..". I need to read the susv4 shell stuff thoroughly, it's been
years...)
Felix
Rob
_______________________________________________
Toybox mailing list
[email protected]
http://lists.landley.net/listinfo.cgi/toybox-landley.net
