Re: Default PATH setting - reduce to something more sensible?

Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:

On 24.01.2025 23:00, Keith Thompson wrote:

Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:

On 24.01.2025 14:46, Dan Cross wrote:

[...]
 
/usr/bin/which is limited in what it can do.  It follows POSIX-specified
behavior for $PATH; it doesn't recognize any shell-specific rules. [...]

>
Sure.
>

[...]

The settings  PATH=~/bin  and  PATH="~/bin"  respectively shall
result in the same behavior across shells when searching for
programs; in the first case looking into "/home/someuser/bin/"
and in the second case looking into "./~/bin/" (i.e. a path
component with a local directory named "~").

 
What do you mean by "shall result?

>
I mean that a shell should behave consistently. (I think Bash does
not in the given case.)

Consistently with what?  Bash consistently expands literal '~'s in
$PATH, and consistently disables that expansion in POSIX mode.

All shells have shell-specific features.  What's odd about this case is
that bash has a POSIX-violating feature that affects command name
resolution.

If this particular feature were documented, I'd have less of a problem
with it (but I'd still avoid using it).

All shells that conform to POSIX behave as you describe.  bash doesn't
conform to POSIX unless you ask it to.  Neither do csh, tcsh, and fish.

I should have mentioned that csh, tcsh, and fish don't conform to POSIX
at all.

We were speaking about shell programming, so [seriously] I don't
consider Csh and Tcsh as sensible sample shells for the discussion.
(Thinking about it, I wonder whether Bash inherited tilde-handling
from Csh, maybe; that would at least explain something.)

No, csh and tcsh (at least in current versions) don't expand literal
'~'s in $PATH.

(I don't know Fish, so I cannot comment on that.)

Nor do I.

I don't mind excluding non-Bournish shells like csh, tcsh, and
fish from the discussion, but I like to mention now and then that
they're being excluded.  They are shells, after all.

[...]

>

BTW, it hadn't occurred to me that you can have a relative path in a
component of $PATH, but it does seem to work.  I won't be taking
advantage of this information.

>
Yes. Some prefer to add '.' to PATH. (Though I have no intention
to discuss that habit.)

Right, of course '.' is a relative path.  I should have thought of that.

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */