newsyslog can't execute command?

Oliver Fromme olli at
Wed Sep 16 13:39:28 UTC 2009

Ferdinand Goldmann wrote:
 > Have I overlooked something, or is it not possible with newsyslog to run a
 > certain command after log rotation? :-(

That's correct.

A simple workaround is to write a small shell script that
stores its PID in a file, then runs in the background and
waits for a signal.  It's a hack, but it works.

Basically, something like this will do:

 #!/bin/sh -
 echo $$ > /var/run/
 while :; do
 	kill -STOP $$
 	do whatever you want with the log file

Make sure that shell script is run in the background
during system boot.

The newsyslog.conf entry should look like this:

/var/log/foo.log     644  3  100  *  B  /var/run/ 19

The important thing is the number "19" at the end, which
will cause newsyslog to send SIGCONT to the shell script
after it has rotated the log file.

Alternatively you can also use the shell's built-in "trap"
command to use different signals.

Best regards

Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

FreeBSD-Dienstleistungen, -Produkte und mehr:

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Our software 'escapes', leaving a bloody trail of designers and quality
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