tail

Additional Notes

tail prints the last part of a file. By default, it shows the last 10 lines.

It is especially useful for logs because tail -f follows new lines as they are written.

Syntax

tail [options] [file...]

Parameters

• options: Flags that change how tail behaves.
• file: Text file to read or process.

Common Options

• -n N, --lines=N: Print the last N lines.
• -c N, --bytes=N: Print the last N bytes.
• -f, --follow: Keep watching the file for new lines.
• -F: Follow by filename and retry if the file is rotated or recreated.
• -q, --quiet: Do not print file headers.
• -v, --verbose: Always print file headers.

Examples

tail app.log

Show the last 10 lines.

tail -n 50 app.log

Show the last 50 lines.

tail -f /var/log/syslog

Follow a log file live.

tail -F /var/log/nginx/access.log

Follow a log even if it is rotated.

journalctl -u ssh -f

For systemd services, this is often a better live-log command.

Practical Notes

• Press Ctrl+C to stop tail -f.
• Use tail -F for logs that may rotate.
• Use grep with tail to filter live logs: tail -f app.log | grep error.
• Use head to view the start of a file.