Tag Archives: screenshot

The command command

According to the 2018 edition of The Open Group Base Specifications (Issue 7), there’s a command named command which executes commands.

Wait, macOS is OpenGroup UNIX 03 certified, right?

command running uname -a

I tried tracing back the history, macOS is mostly based on FreeBSD, as we can see in their open-source code.

So I started tracing back the FreeBSD code, and I found the current one.

I found the oldest commit about command in FreeBSD’s source tree, but it said

Import the 4.4BSD-Lite2 /bin/sh sources

builtins.def

So I opened up the SVN tree of CSRG, and there I found this

date and time created 91/03/07 20:24:04 by bostic

builtins.def

However, if I knew how to use SVNWeb, I’m pretty sure I’d navigate around the /old/sh directory.

It’s funny, how this line
# NOTE: bltincmd must come first!
Is both in the macOS code AND the CSRG code from 30 years ago.

That’s all folks…