Re: [PATCH] Add shell-quasiquote.

[Andreas Schwab]

David Kastrup <address@hidden> writes:

> Eli Zaretskii <address@hidden> writes:
>
>>> From: David Kastrup <address@hidden>
>>> Cc: Eli Zaretskii <address@hidden>, address@hidden,
>>> address@hidden, address@hidden
>>> Date: Thu, 22 Oct 2015 14:47:26 +0200
>>> 
>>> [/bin/sh] is what "system" is supposed to run.
>>
>> Maybe I'm wrong, but my reading of Posix indicates that 'system' runs
>> "sh" in an unspecified directory.
>
> <URL:http://pubs.opengroup.org/onlinepubs/9699919799/>
>
>     [CX] [Option Start] The system() function shall behave as if a child
>     process were created using fork(), and the child process invoked the
>     sh utility using execl() as follows:
>
>     execl(<shell path>, "sh", "-c", command, (char *)0);
>
>     where <shell path> is an unspecified pathname for the sh utility.
>     [...]
>
> Well, you're quite right.  It's not even necessary that the executable
> file in the unspecified directory is actually called "sh" as long as it
> is called with argv[0] being "sh".

That's because file system hierarchy is outside the scope of POSIX
(execept for a few items as specified in 10.1 Directory Structure and
Files).  In Unix, <shell path> is always "/bin/sh".

Andreas.

-- 
Andreas Schwab, SUSE Labs, address@hidden
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