tail flags & options

-n, --lines

Output the last N lines instead of the default 10.

tail -n 20 file.txt

tail -n +5 file.txt

-f, --follow

Output appended data as the file grows.

tail -f /var/log/syslog

tail -f -n 50 app.log

-F

Same as --follow=name --retry; follow by name and keep trying if inaccessible.

tail -F /var/log/app.log

-c, --bytes

Output the last N bytes.

tail -c 100 file.txt

tail -c +200 file.txt

--pid

With -f, terminate after the process with the given PID dies.

tail -f --pid=1234 app.log

-q, --quiet

Never output headers giving file names.

tail -q -n 5 file1.txt file2.txt