Linux – proper way to clear logs

linuxloggingUbuntu

I was wondering if there was a proper way to clear logs in general?

I'm new to Ubuntu and I'm trying to set up Postfix. The log in question is /var/log/mail.log. I was wondering if there was a correct way to clear it, rather than me going in it and deleting all the lines and saving it. I find that sometimes errors don't get written to it immediately after I clear the log and save it.

Side note: I'm having trouble setting up Postfix and am trying to make it easier for me to read the logs hoping it can help me out, instead of having to scroll all the way down.

Best Answer

You can use:

> /var/log/mail.log

That will truncate the log without you having to edit the file. It's also a reliable way of getting the space back.

In general it's a bad thing to use rm on the log then recreating the filename, if another process has the file open then you don't get the space back until that process closes it's handle on it and you can damage it's permissions in ways that are not immediately obvious but cause more problems later on.

Yasar has a nice answer using truncate

Also if you are watching the contents of the log you might like to use the tail command:

tail -f /var/log/mail.log

Ctrl-C will break off the tailing.

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