[TUHS] Shell control through external commands

Ronald Natalie ron at ronnatalie.com
Fri Jul 15 09:10:57 AEST 2016


> On Jul 14, 2016, at 6:36 PM, Dave Horsfall <dave at horsfall.org> wrote:
> 
> On Thu, 14 Jul 2016, Clem Cole wrote:
> 
>> Could you be confusing the fact the true and false were implemented by
>> external commands in some early shell's
> 
> And on the Mac and FreeBSD, they still are (as well as being builtins).
> 
> At one time they were shell scripts e.g. "exit 0" for "true".

Actually, one of the UNIX releases had NO EXECUTABLE CODE in /bin/true.   The default is to return the true.
There was 20 lines of copyright/rights notice in commends.


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