Syslog
Syslog collects log data from multiple programs either to RAM or to a file, and handles log rotation (similar to journald on systemd-based systems). Alpine installs syslog as provided by busybox per default, but it also packages other implementations, such as rsyslog, syslog-ng and logbookd.
busybox syslog
Running syslogd
Depending on how you have installed Alpine, it is already running (check with ps a | grep syslogd). Otherwise enable it at boot and start it with the following commands:
# rc-update add syslog boot # rc-service syslog start
Configuration
Edit /etc/conf.d/syslog to change the options used when running syslogd. All available options can be looked up with syslogd --help.
Reading logs
# tail -f /var/log/messages Shows all messages and follows the log # tail -f /var/log/messages | grep ssh Only shows SSH related messages, also follows the log
When -C is enabled in the configuration:
# logread -f # logread -f | grep ssh
Writing logs
Many applications are able to write to the syslog by default (e.g. sshd). If you wish to write manually to it, use the logger program.
$ logger "hello world"