Log File Navigator

Charly's Column – lnav

Article from Issue 223/2019

During a long trek through the verbose syslog, really important warnings and errors are scattered along the path. Sometimes a missing message can be the decisive event. Sys admin columnist Charly has now hired a tracker to help him search for clues: Log File Navigator.

Searching in logfiles is the sys admin's bread and butter. Finding a specific piece of information often requires long cascades of grep commands. What makes this even more difficult is if a log message that I expect every five minutes is delayed. Of course, this is a warning signal, but I can't use grep to figure this out. What can draw my attention to the fact that warning messages are piling up? These difficulties prompted me to onboard Log File Navigator (lnav, [1] ).

If you launch lnav without any options, it opens /var/log/syslog (Figure 1). Using:

lnav /var/log/syslog*


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