[TUHS] Shell control through external commands
arnold at skeeve.com
arnold at skeeve.com
Fri Jul 15 12:25:27 AEST 2016
Dave Horsfall <dave at horsfall.org> wrote:
> On Thu, 14 Jul 2016, shawn wilson wrote:
>
> > I've always been curious though - what was the reason behind
> > implementing /bin/[ ? IDK any shell where this isn't implemented - I
> > always assumed it's a POSIX compatibility stopgap older systems needed
> > to stay compliant with their shipped shell.
>
> To implement:
>
> [ blah ]
>
> when it wasn't a built-in (there were few built-ins in those days).
>
> I have no idea why it's still there... A Posix requirement, along with
> really unsafe functions?
Consider
execlp("[", "-f", "/some/file", "]", NULL);
Then [ and test need to live in the filesystem.
Arnold
More information about the TUHS
mailing list