Linux head command
On Unix-like operating systems, the head command outputs the first part (the head) of a file or files.
head, by default, prints the first 10 lines of each FILE to standard output. With more than one FILE, it precedes each set of output with a header identifying the file name. If no FILE is specified, or when FILE is specified as a dash ("-"), head reads from standard input.
head [OPTION]... [FILE]...
|-c, --bytes=[-]num||Print the first num bytes of each file; with a leading '-', print all but the last num bytes of each file.|
|-n, --lines=[-]num||Print the first num lines instead of the first 10; with the leading '-', print all but the last num lines of each file.|
|-q, --quiet, --silent||Never print headers identifying file names.|
|-v, --verbose||Always print headers identifying file names.|
|--help||Display a help message and exit.|
|--version||Output version information and exit.|
In the above options, num may have a multiplier suffix:
Display the first ten lines of myfile.txt.
head -15 myfile.txt
Display the first fifteen lines of myfile.txt.
head myfile.txt myfile2.txt
Display the first ten lines of both myfile.txt and myfile2.txt, with a header before each that indicates the file name.
head -n 5 myfile.txt myfile2.txt
Displays only the first 5 lines of both files.
head -c 20 myfile.txt
head -n 5K myfile.txt
Displays the first 5,000 lines of myfile.txt.
head -c 6M myfile.txt
Displays the first six megabytes.
If a dash is specified for the file name, head reads from standard input rather than a regular file.
head myfile.txt myfile2.txt -
Display the first ten lines of myfile.txt, myfile2.txt, and standard input.
head -n 4 *.txt
Display the first four lines of every file in the working directory whose file name ends in the extension .txt.
head -n 4 -q *.txt
Same as the previous command, but uses quiet (-q) output, which will not print a header before the lines of each file.