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logging levels with systemd (discuss.tchncs.de)

submitted 3 months ago by MoLoPoLY@discuss.tchncs.de to c/linuxquestions@lemmy.zip

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I start a bash shell script via a oneshot unit. I output standard messages currently with

echo $message
echo $message >> $logfile.txt

With this I have output on screen and additionally in a logfile. I don't know if there is a better way to do that.

This works for standard infos fine. Additionally there must be a way to output also error messages and warnings, since when I look into other services, I see red messages for errors and yellow/orange colored messages for warnings.

How can I do such things with my bash script and output other levels like warnings in yellow and errors in red?

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[–] Jackinopolis@sh.itjust.works 2 points 3 months ago (1 children)

It's been a minute since I've looked into logging. Syslog is the OG standard, but generally improved with rsyslog and journald. You'll have logging levels with these and can be colored/filtered in a viewing program.

[–] MoLoPoLY@discuss.tchncs.de 2 points 3 months ago

Many thx for the hint with journald. A little bit searching gives me https://serverfault.com/questions/573946/how-can-i-send-a-message-to-the-systemd-journal-from-the-command-line

I try that tomorrow. From reading it seems to be, what I need.

[–] Chais@sh.itjust.works 2 points 3 months ago* (last edited 3 months ago)

AFAIK the general approach to logging with systemd is that the application simply writes to stdout/stderr and systemd takes care of passing the output to whatever logging target/s you configured.
As for signaling log levels with bash, you can write functions that prepend any timestamps, markers or wrap the string in any color codes you want.