What is Head Command?
head is a program on Unix and Unix-like operating systems used to display the beginning of a text file or piped data.
What is Tail Command?
tail is a program available on Unix, Unix-like systems and FreeDOS used to display the end of a text file or piped data.
How to use Head Command?
By default head command list first ten lines of a file. In this example i will show you the first ten lines of /etc/shadow file.
See desired number of lines using head command
Now, you will see first 20 lines of /etc/shadow file
-n used to define lines.
20 it is number of lines
head -n20 /etc/shadow
How to use Tail Command?
Like head command, tail is also display 10 lines by default but these are last 10 lines of a file. use following command to list last lines of a file.
So if you want to see last 20 lines of /etc/shadow file. Then run below command
tail -n20 /etc/shadow