Build[1][2] Docs[3][4] Coverage Status[5][6] lnav[7][8] ▌[1] - https://github.com/tstack/lnav/workflows/ci-build/badge.svg ▌[2] - https://github.com/tstack/lnav/actions?query=workflow%3Aci-build ▌[3] - https://readthedocs.org/projects/lnav/badge/?version=latest&style=plastic ▌[4] - https://docs.lnav.org ▌[5] - https://coveralls.io/repos/github/tstack/lnav/badge.svg?branch=master ▌[6] - https://coveralls.io/github/tstack/lnav?branch=master ▌[7] - https://snapcraft.io//lnav/badge.svg ▌[8] - https://snapcraft.io/lnav This is the source repository for lnav, visit https://lnav.org[1] for a high level overview. ▌[1] - https://lnav.org LNAV – The Logfile Navigator The Log File Navigator, lnav for short, is an advanced log file viewer for the small-scale. It is a terminal application that can understand your log files and make it easy for you to find problems with little to no setup. Screenshot The following screenshot shows a syslog file. Log lines are displayed with highlights. Errors are red and warnings are yellow. Screenshot[1][2] ▌[1] - file://{top_srcdir}/docs/assets/images/lnav-syslog-thumb.png ▌[2] - file://{top_srcdir}/docs/assets/images/lnav-syslog.png Features • Log messages from different files are collated together into a single view • Automatic detection of log format • Automatic decompression of GZip and BZip2 files • Filter log messages based on regular expressions • Use SQL to analyze your logs • And more... Installation Download a statically-linked binary for Linux/MacOS from the release page[1] ▌[1] - https://github.com/tstack/lnav/releases/latest#release-artifacts Usage The only file installed is the executable,  lnav . You can execute it with no arguments to view the default set of files: ▌$ lnav  You can view all the syslog messages by running: ▌$ lnav /var/log/messages*  Usage with  systemd-journald  On systems running  systemd-journald , you can use  lnav  as the pager: ▌$ journalctl | lnav  or in follow mode: ▌$ journalctl -f | lnav  Since  journalctl 's default output format omits the year, if you are viewing logs which span multiple years you will need to change the output format to include the year, otherwise  lnav  gets confused: ▌$ journalctl -o short-iso | lnav  It is also possible to use  journalctl 's json output format and  lnav will make use of additional fields such as PRIORITY and _SYSTEMD_UNIT: ▌$ journalctl -o json | lnav  In case some MESSAGE fields contain special characters such as ANSI color codes which are considered as unprintable by journalctl, specifying  journalctl 's  -a  option might be preferable in order to output those messages still in a non binary representation: ▌$ journalctl -a -o json | lnav  If using systemd v236 or newer, the output fields can be limited to the ones actually recognized by  lnav  for increased efficiency: ▌$ journalctl -o json --output-fields=MESSAGE,PRIORITY,_PID,SYSLOG_IDENTIFIER,_SYSTEMD_UNIT | lnav  If your system has been running for a long time, for increased efficiency you may want to limit the number of log lines fed into  lnav , e.g. via  journalctl 's  -n  or  --since=...  options. In case of a persistent journal, you may want to limit the number of log lines fed into  lnav  via  journalctl 's  -b  option. Links • Main Site[1] • Documentation[2] on Read the Docs • Internal Architecture[3] ▌[1] - https://lnav.org ▌[2] - https://docs.lnav.org ▌[3] - file://{top_srcdir}/ARCHITECTURE.md Contributing • Become a Sponsor on GitHub[1] ▌[1] - https://github.com/sponsors/tstack Building From Source Prerequisites The following software packages are required to build lnav: • gcc/clang - A C++14-compatible compiler. • libpcre - The Perl Compatible Regular Expression (PCRE) library. • sqlite - The SQLite database engine. Version 3.9.0 or higher is required. • ncurses - The ncurses text UI library. • readline - The readline line editing library. • zlib - The zlib compression library. • bz2 - The bzip2 compression library. • libcurl - The cURL library for downloading files from URLs. Version 7.23.0 or higher is required. • libarchive - The libarchive library for opening archive files, like zip/tgz. • wireshark - The 'tshark' program is used to interpret pcap files. Build Lnav follows the usual GNU style for configuring and installing software: Run  ./autogen.sh  if compiling from a cloned repository. ▌$ ./configure  ▌$ make  ▌$ sudo make install  See Also Angle-grinder[1] is a tool to slice and dice log files on the command-line. If you're familiar with the SumoLogic query language, you might find this tool more comfortable to work with. ▌[1] - https://github.com/rcoh/angle-grinder