Introduction

The Log File Navigator, lnav, is an enhanced log file viewer that takes advantage of any semantic information that can be gleaned from the files being viewed, such as timestamps and log levels. Using this extra semantic information, lnav can do things like interleaving messages from different files, generate histograms of messages over time, and providing hotkeys for navigating through the file. It is hoped that these features will allow the user to quickly and efficiently zero in on problems.

Dependencies

When compiling from source, the following dependencies are required:

• NCurses
• PCRE – Versions greater than 8.20 give better performance since the PCRE JIT will be leveraged.
• SQLite
• ZLib
• Bzip2
• Readline

Installation

Check the downloads page to see if there are packages for your operating system. Compiling from source is just a matter of doing:

$ ./configure
$ make
$ sudo make install

Viewing Logs

The arguments to lnav are the log files, directories, or URLs to be viewed. For example, to view all of the CUPS logs on your system:

$ lnav /var/log/cups

The formats of the logs are determined automatically and indexed on-the-fly. See Log Formats for a listing of the predefined formats and how to define your own.

If no arguments are given, lnav will try to open the syslog file on your system:

$ lnav