Tailing Logs with less

September 22, 2014

less is already an incredibly useful command in linux (GNU/linux for the purists). It’s a better version of more, for paging through files. One not so well known switch for less is the following:

less +F [file]

The +F option tails the end of the log. Updating when the log changes is buffered, so depending on how noisy your log file is there may be some delay in seeing updates.

At any time when less is in tailing mode you can hit CTRL+C to return to regular less. The status bar reminds you of this with a message like interrupt to abort. This feature is incredibly powerful, for example if something at the bottom of the log catches your eye and you want to stop tailing for a moment so you can check the logs around it.

In regular-mode less, pressing shift+F will put you into tailing mode. This is true even if you started less without the +F option.