LinuxCommandLibrary

lnav

Advanced log file viewer to analyze logs with little to no setup.

TLDR

View logs of a program, specifying log files, directories or URLs

$ lnav [path/to/log_or_directory|url]
copy


View logs of a specific remote host (SSH passwordless login required)
$ lnav [ssh] [user]@[host1.example.com]:[/var/log/syslog.log]
copy


Validate the format of log files against the configuration and report any errors
$ lnav -C [path/to/log_directory]
copy

SYNOPSIS

lnav [-hVsar] [logfile1 logfile2 ...]

DESCRIPTION

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.

KEY BINDINGS

?

View/leave the online help text.

q

Quit the program.

OPTIONS

-h

Print help and exit

-H

Display the internal help text.

-I path

Add the given configuration directory to the search path.

-i

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

-C

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.

-d file

Write debug messages to the given file.

-V

Print version information.

-a

Load all of the most recent log file types.

-r

Recursively load files from the given directories.

-R

Load older rotated log files as well.

-t

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

-w file

Write the contents of the standard input to this file.

Optional arguments:

logfile1

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

EXAMPLES

To load and follow the syslog file:

lnav

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

AUTHOR

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

Copied to clipboard