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@@ -5,51 +5,95 @@ [](https://coveralls.io/github/tstack/lnav?branch=master) [](https://snapcraft.io/lnav) -[<img src="https://assets-global.website-files.com/6257adef93867e50d84d30e2/62594fddd654fc29fcc07359_cb48d2a8d4991281d7a6a95d2f58195e.svg" height="20"/>](https://discord.gg/erBPnKwz7R) +[<img src="https://assets-global.website-files.com/6257adef93867e50d84d30e2/62594fddd654fc29fcc07359_cb48d2a8d4991281d7a6a95d2f58195e.svg" height="20" alt="Discord Logo"/>](https://discord.gg/erBPnKwz7R) _This is the source repository for **lnav**, visit [https://lnav.org](https://lnav.org) for a high level overview._ # 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. +The Logfile Navigator 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](https://docs.lnav.org/en/latest/formats.html#json-lines). + +Then, in the **lnav** TUI, you can: + +- jump quickly to the previous/next error ([press `e`/`E`](https://docs.lnav.org/en/latest/hotkeys.html#spatial-navigation)); +- search using regular expressions ([press `/`](https://docs.lnav.org/en/latest/hotkeys.html#spatial-navigation)); +- highlight text with a regular expression ([`:highlight`](https://docs.lnav.org/en/latest/commands.html#highlight-pattern) command); +- filter messages using [regular expressions](https://docs.lnav.org/en/latest/usage.html#regular-expression-match) or [SQLite expressions](https://docs.lnav.org/en/latest/usage.html#sqlite-expression); +- pretty-print structured text ([press `P`](https://docs.lnav.org/en/latest/ui.html#pretty)); +- view a histogram of messages over time ([press `i`](https://docs.lnav.org/en/latest/ui.html#hist)); +- query messages using SQLite ([press `;`](https://docs.lnav.org/en/latest/sqlext.html)) ## Screenshot -The following screenshot shows a syslog file. Log lines are displayed with -highlights. Errors are red and warnings are yellow. +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. + +[](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: -[](docs/assets/images/lnav-syslog.png) +[`$ ssh playground@demo.lnav.org`](ssh://playground@demo.lnav.org) -## Features +The "tutorial 1" account is an interactive tutorial that can teach +you the basics of operation: -- 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... +[`$ ssh tutorial1@demo.lnav.org`](ssh://tutorial1@demo.lnav.org) ## Installation [Download a statically-linked binary for Linux/MacOS from the release page](https://github.com/tstack/lnav/releases/latest#release-artifacts) +### Brew on MacOS + +```console +$ brew install lnav +``` + ## Usage -The only file installed is the executable, `lnav`. You can execute it -with no arguments to view the default set of files: +Simply point **lnav** at the files or directories you want to +monitor, it will figure out the rest: -``` -$ lnav +```console +$ lnav /path/to/file1 /path/to/dir ... ``` -You can view all the syslog messages by running: +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). -``` -$ lnav /var/log/messages* -``` +See the [Usage section](https://docs.lnav.org/en/latest/usage.html) +of the online documentation for more information. + +[^1]: Files that do not contain log messages can be seen in the + TEXT view (reachable by pressing `t`). ### Usage with `systemd-journald` @@ -138,6 +182,7 @@ The following software packages are required to build lnav: - 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 |