From mboxrd@z Thu Jan  1 00:00:00 1970
From: ron@ronnatalie.com (Ronald Natalie)
Date: Thu, 14 Jul 2016 19:10:57 -0400
Subject: [TUHS] Shell control through external commands
In-Reply-To: <alpine.BSF.2.11.1607150835460.65801@aneurin.horsfall.org>
References: <4fcf31ef-50af-10b5-0c34-ad647ed10a4e@aueb.gr>
 <CAC20D2Mho6xh+LPucpXmt7QjJge+qc59LYaF+wfhrm3QVOLpWg@mail.gmail.com>
 <alpine.BSF.2.11.1607150835460.65801@aneurin.horsfall.org>
Message-ID: <0A01A2D5-ADB2-43C4-807A-04B3D12F2B70@ronnatalie.com>


> 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.