Re: s6-log run script

From: Laurent Bercot <>
Date: Thu, 3 Mar 2016 02:09:23 +0100

On 02/03/2016 23:52, Jan Olszak wrote:
> #!/usr/bin/execlineb -P
> if -nt
> {
> backtick -n S6_LOG_ARGS
> {
> redirfd -r 0 /opt/s6logargs.opts s6-cat
> }
> import -u S6_LOG_ARGS s6-log T $S6_LOG_ARGS
> }
> s6-log T s1000000 n10 /var/log/syslogd

  That won't work for several reasons:

  * the if -nt will only return once s6-log returns. Since s6-log is a
long-lived program, that won't happen unless there's an error in the
s6-log invocation. Which is what is happening here.

  * execline is not like the shell: when you import S6_LOG_ARGS, it is
evaluated as just one word - it's not split. So your s6-log invocation
is given two arguments: T, and whatever is in S6_LOG_ARGS. Likely
s6-log cannot interpret the contents of your opts file as one single
argument, so it fails - and dies, and if returns, and you get the

  * Even if s6-log succeeded, you'd have the "if" process hanging around,
and s6-log would be a child of if. That's not what you want: you always
want the process to execute into your chosen avatar of s6-log in the end.

  Try something like this:

backtick -n -D "s1000000 n10 /var/log/syslogd" S6_LOG_ARGS
   redirfd -r 0 /opt/s6logargs.opts s6-cat
import -u -s S6_LOG_ARGS # notice the -s, to split the args
s6-log T ${S6_LOG_ARGS}

  Also, traditionally, /opt is not a good place to store regular files,
even global ones - you'd use /etc or a subdirectory of /etc for that.
But that's your business. :)

Received on Thu Mar 03 2016 - 01:09:23 UTC

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