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The Logfile Navigator, lnav for short, is a curses-based tool for viewing and analyzing log files. The value added by lnav over text viewers / editors is that it takes advantage of any semantic information that can be gleaned from the log file, 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.


The standard view of a syslog file. Log lines are displayed with highlights. Errors are red and warnings are yellow. The histogram view of the same syslog file. The histogram shows the number of messages per time slice.


Source: Binaries:


The major features of lnav are:

See the on-line help text for more information.

Interface Tour

Top bar: Displays the current time, the number of warnings and errors above the top line and the name of the file where the top line came from.

Main content: Displays the log lines in time sorted order and highlighted. Highlights are done for: errors, warnings, search terms, quoted strings, and some SQL syntax. On the far right, there is a proportional scroll bar displayed in reverse-video that shows the current position in the file.

Bottom bar: Displays the current line number, the position in the file as a percentage, warnings and errors below the bottom line.

Entry line: Searches and commands are entered here. The entry line supports tab-completion in most contexts and displays suggestions in the entry box. In this screenshot, the user is typing in a SQL query. The top shows an error message indicating that the SQL statement is incomplete. Queries and searches are automatically checked for correctness as you type. The screenshot also shows suggestions for SQL keywords and column names after the user hit the TAB key twice.


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