[TUHS] Shell control through external commands

[Tony Finch]

Joerg Schilling <schily at schily.net> wrote:
>
> The colon was introduced by AT&T around 1983.

It's a builtin in the v7 Bourne shell - see SYSNULL in msg.c (which
has the command name table) and in xec.c (which has the implementation)

http://www.tuhs.org/Archive/PDP-11/Trees/V7/usr/src/cmd/sh/

Tony.
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