[TUHS] Shell control through external commands
Random832
random832 at fastmail.com
Fri Jul 15 12:25:31 AEST 2016
On Thu, Jul 14, 2016, at 19:56, 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.
It's required because it might be executed by non-shell programs.
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html#tag_17_06
My Mac even has /usr/bin/cd.
The "special builtins" which aren't required to exist as binaries are:
break : continue . eval exec exit export readonly return set shift
times trap unset
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