Hi,

Mathieu Othacehe <othacehe@gnu.org> skribis:

> From 18754c8c62eabb341e0f710d83ff435ef950ca8e Mon Sep 17 00:00:00 2001
> From: Mathieu Othacehe <othacehe@gnu.org>
> Date: Mon, 8 Jun 2020 15:14:49 +0200
> Subject: [PATCH] installer: utils: Dump command output to syslog when testing.
>
> When debugging the installation tests, it can be very handy to be able to read
> "run-command" output, for instance when executing "guix system init".
>
> Introduce a new "invoke-with-log" procedure that is able to log a command
> standard and error outputs to the syslog. Use it, only when running the
> installation tests, to dump "run-command" output.
>
> * gnu/installer/utils.scm (open-pipe-with-stderr, invoke-with-log): New
> procedures,
> (invoke-log-port): new variable,
> (run-command): move to the end of the file and use invoke-with-log when
> running the installation tests.
> ---
>  gnu/installer/utils.scm | 164 +++++++++++++++++++++++++++++-----------
>  1 file changed, 120 insertions(+), 44 deletions(-)

It’s nice, but also a bit complicated just to print stuff on the
screen.  :-)

I found a stash with my debugging hack: