By default, it displays the first lines when used in the form:
head [filename]
head -n 11 [filename] -> First 11 lines
head -c 20 [filename] -> First 20 characters
Since we will provide the text files via STDIN the filename may be ignored.
We can also specify a certain number of lines to be displayed and list multiple filenames as well. It may also be used to display a specified number of bytes from an input file. Click here for more details about using the head command.