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lnav - Man Page

log file viewer for the terminal

Examples (TL;DR)


lnav [options] [logfile1 logfile2 ...]


The Logfile Navigator, lnav, is a log file viewer for the terminal. Given a set of files/directories, lnav will:

- decompress as needed;

- detect their format;

- merge the files together by time into a single view;

- tail the files, follow renames, find new files in directories;

- build an index of errors and warnings;

- pretty-print JSON-lines.

Key Bindings


View/leave the online help text.


Quit the program.



Print help and exit


Display the internal help text.

-I path

Add the given configuration directory to the search path.


Print warnings related to lnav's configuration.


Update formats installed from git repositories.

-d file

Write debug messages to the given file.


Print version information.


Recursively load files from the given directories.


Load older rotated log files as well.

-c cmd

Execute a command after the files have been loaded.

-f path

Execute the commands in the given file.

-e cmd

Execute a shell command-line.


Prepend timestamps to the lines of data being read in on the standard input.


Run without the curses UI.  (headless mode)


Do not open the default syslog file if no files are given.


Quiet mode.  Do not print the log messages after executing all of the commands.

Optional arguments


The log files or directories to view.  If a directory is given, all of the files in the directory will be loaded.

Management-Mode Options


Install the given format files in the $HOME/.lnav/formats/installed directory and exit.


Switch to the management command-line mode.  This mode is used to work with lnav's configuration.


Check the configuration and exit.  The log format files will be loaded and checked.  Any files given on the command-line will be loaded checked to make sure they match a log format.


To load and follow the syslog file:


To load all of the files in /var/log:

    lnav /var/log

To watch the output of make with timestamps prepended:

    make 2>&1 | lnav -t


This manual page was written by Salvatore Bonaccorso <carnil@debian.org> for the Debian system (but may be used by others).


April 2024