Telling journalctl to show all but a certain facility

Bram

4/22/24, 6:14 PM

I'm trying to get rid of dhcpd spam in my journal.

Using rsyslog.conf and dhcpd.conf I have been able to keep it out of /var/log/syslog and put it in /var/log/dhcpd.log which is great.

However, journalctl will still show the dhcpd spam.

How do I instruct journalctl to use an "everything-but-X" filter?

I don't want to type

$ journalctl --facility=kern,user,mail,....,local7

But invert the logic to something like:

$ journalctl --facility=!local7

But that latter syntax is incorrect. Is there a way to achieve this? Or else, filter on !dhcpd or something?

112

1 + 2

dhcpd

systemd-journald

Raffa

4/22/24, 6:33 PM

AFAIK it doesn't support negation ... However, you can filter with e.g. `... | grep -v "word" | less`

Bram

4/22/24, 7:23 PM

@raffa Thank you. Once piped through another program, the log loses all colour encodings. So no longer red errors, yellow warnings. I need the option in systemctl itself.

Score:0

Ubuntu

Raffa

4/22/24, 11:44 PM

Unfortunately, journalctl doesn't seem to support that kind of excluding output by negating a certain facility.

Possible workarounds are:

Using grep with the -v, --invert-match option like so:
```
journalctl | grep --line-buffered -v 'pattern'
```
Using grep with ccze(needs install) log colorizer for color coded output like so:
```
journalctl | grep --line-buffered -v 'pattern' | ccze -A
```
Using journalctl builtin -g, --grep= option with PCRE2 regular expressions pattern to filter entries by the message field like so:
```
journalctl --grep='pattern'
```
This one will be tricky to negate a string, but your best bet might be to include negative lookarounds.

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EN: Telling journalctl to show all but a certain facility

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