XpoLog help - Tail
XpoLog enables you to perform tailing on a log or a merged log. 
Tailing
In the log view screen you have an option to tail a log that you are viewing. When you will press 'Tail' you will notice that the browser is automatically performs a refresh action every 1.5 seconds, by that the new records that were produced in the log file will be loaded and will appear in the log view screen of XpoLog. 
In order to view online changing files, which can be useful for debugging, click on tail link, the log viewer will change to tail mode updating the view with new records from the logs, if a filter is active the records presented will be the ones allowed by the filter rules.
By default the number of records accumulates while tailing is 500 and the tailing rate is every 2 seconds. You can set these properties under Settings, Log View Settings.
Additional links
      
Merge help page
       Add a log
       Log customization help