Per Journald man page. This command can capture stdout/stderr, only, for running services. However, sometimes we would like to capture text logs into journald, For example, nginx access.log.
Is it possible to capture any text file using command such as tail -f into journald with systemd tools?
You can accomplish this using the method discussed in this SF Q&A titled: How can I send a message to the systemd journal from the command line?. This method uses the tool systemd-cat which is similar in functionality to logger.
$ echo 'hello' | systemd-cat -p info
$ echo 'hello' | systemd-cat -p warning
$ echo 'hello' | systemd-cat -p emerg
Messages would show up like this in journald:
Feb 07 13:38:33 localhost.localdomain cat[15162]: hello
You can control the identifier details that show up in the logs like this:
$ echo 'hello' | systemd-cat -t someapp -p emerg
Resulting in this type of logging:
Feb 07 13:48:56 localhost.localdomain someapp[15278]: hello
NOTE: I'd still probably implement this using an actual systemd unit file designed to capture the logs of Nginx.
