How to Watch a File in Linux using tail
We all know how we can view files using
less, but one command that I find very useful is the
Similar to the
head command, it prints part of a file. But unlike
head, it prints the last part of a file.
tail [flags] [file]
By default, running
tail on a file will print the last 10 lines of that file.
tail -n k [file] option will allow us to print the last
k lines of a file.
tail -n 5 file.txt
I don’t see myself using
-n that often, though. I do see myself using
-f quite often.
-f by itself will print the last 10 lines of the file and then wait for new lines to be added to the file.
tail -f file.txt
It essentially waits and watches the file for something to be appended to it.
This is especially useful when you have a script or program running that outputs some results to a log file (usually a text file). You can just watch or “follow” (hence the
-f) that log file in that terminal.
You can break out of this process by pressing