tailf

View documentation for the recommended replacement

$ tldr tail

tailf [ options ] file

-n number
    Output the last number lines, instead of the last 10.

-f
    Does nothing; kept for backward compatibility. It's implied.

file
    The file to be monitored.

The tailf command in Linux is a specialized version of the tail command specifically designed for tracking changes to log files.
Unlike the regular tail command, tailf doesn't stop when it reaches the end of the file. Instead, it remains active and continues to monitor the file for new content. This makes it ideal for real-time monitoring of log files and other files that are frequently appended to.
tailf achieves this functionality by periodically checking if the file has grown. If it detects new content, it outputs the new lines to the console. tailf will continue to operate until it is manually terminated (e.g., with Ctrl+C).
While it was widely used, tailf has been largely superseded by the more robust and versatile tail -f command, as tail -f provides enhanced functionality, like being able to track file moves and rotations. However, tailf remains available on some systems and can still be useful in certain scenarios, particularly when simplicity is desired. It is particularly useful for monitoring files generated by servers, applications or processes which create log messages.

tailf may not handle file rotations gracefully. If the file is renamed or truncated, tailf might stop working. Using tail -F is generally recommended for more robust file tracking. tailf might not be available on all systems.

tailf can fail to track changes if the log file is rotated (e.g., renamed and a new file created). In this case tail -F is recommended. tail -F detects when the file is replaced and automatically opens the new file.

tailf was created as a simplified tool specifically for following log files. Prior to the enhancements of the standard tail command with the -f option, tailf provided a straightforward way to monitor files for new content without requiring complex scripting. The main use was to provide a easy-to-use and lighter alternative to polling a file with tail in a loop. With the improvements of the tail command, tailf is less commonly used nowadays, but remains present as a legacy command on some systems.

tail(1), head(1), less(1), grep(1)