Screenshot The following screenshot shows a mix of syslog and web access log files. Failed requests are shown in red. Identifiers, like IP address and PIDs are semantically highlighted. ]8;;docs/assets/images/lnav-front-page.png\🖼 Screenshot[1]]8;;\[2] ▌[1] - file://{top_srcdir}/docs/assets/images/lnav-front-page.png ▌[2] - file://{top_srcdir}/docs/assets/images/lnav-front-page.png Why not just use  tail / grep / less ? The standard Unix utilities are great for processing raw text lines, however, they do not understand log messages. Tail can watch multiple files at a time, but it won't display messages in order by time and you can't scroll backwards. Grep will only find matching lines, but won't return a full multi-line log message. Less can only display a single file at a time. Also, none of these basic tools handle compressed files. Try online before installing You can SSH into a demo node to play with lnav before installing. The "playground" account starts lnav with a couple of log files as an example: ]8;;ssh://playground@demo.lnav.org\ $ ssh playground@demo.lnav.org ]8;;\[1] ▌[1] - ssh://playground@demo.lnav.org The "tutorial 1" account is an interactive tutorial that can teach you the basics of operation: ]8;;ssh://tutorial1@demo.lnav.org\ $ ssh tutorial1@demo.lnav.org ]8;;\[1] ▌[1] - ssh://tutorial1@demo.lnav.org Installation ]8;;https://github.com/tstack/lnav/releases/latest#release-artifacts\Download a statically-linked binary for Linux/MacOS from the release]8;;\ ]8;;https://github.com/tstack/lnav/releases/latest#release-artifacts\page]8;;\[1] ▌[1] - https://github.com/tstack/lnav/releases/latest#release-artifacts Brew on MacOS ▌$ brew install lnav  Usage Simply point lnav at the files or directories you want to monitor, it will figure out the rest: ▌$ lnav /path/to/file1 /path/to/dir ...  The lnav TUI will pop up right away and begin indexing the files. Progress is displayed in the "Files" panel at the bottom. Once the indexing has finished, the LOG view will display the log messages that were recognized[^1]. You can then use the usual hotkeys to move around the view (arrow keys or  j / k / h / l  to move down/up/left/right). See the ]8;;https://docs.lnav.org/en/latest/usage.html\Usage section]8;;\[1] of the online documentation for more information. ▌[1] - https://docs.lnav.org/en/latest/usage.html [^1]: Files that do not contain log messages can be seen in the TEXT view (reachable by pressing  t ). 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. Support Please file issues on this repository or use the discussions section. The following alternatives are also available: • ]8;;mailto:support@lnav.org\support@lnav.org]8;;\[1] • ]8;;https://discord.gg/erBPnKwz7R\Discord]8;;\[2] • ]8;;https://groups.google.com/g/lnav\Google Groups]8;;\[3] ▌[1] - mailto:support@lnav.org ▌[2] - https://discord.gg/erBPnKwz7R ▌[3] - https://groups.google.com/g/lnav Links • ]8;;https://lnav.org\Main Site]8;;\[1] • ]8;;https://docs.lnav.org\Documentation]8;;\[2] on Read the Docs • ]8;;ARCHITECTURE.md\Internal Architecture]8;;\[3] ▌[1] - https://lnav.org ▌[2] - https://docs.lnav.org ▌[3] - file://{top_srcdir}/ARCHITECTURE.md Contributing • ]8;;https://github.com/sponsors/tstack\Become a Sponsor on GitHub]8;;\[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. • libpcre2 - The Perl Compatible Regular Expression v2 (PCRE2) 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. • cargo/rust - The Rust language is used to build the PRQL compiler. 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 ]8;;https://github.com/rcoh/angle-grinder\Angle-grinder]8;;\[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