Head (Unix)

head is a program on Unix and Unix-like operating systems used to display the beginning of a text file or piped data.

head

Example usage of head command to display first 5 lines of Lorem ipsum in the specified file
Developer(s)	Various open-source and commercial developers
Operating system	Unix, Unix-like, MSX-DOS, IBM i
Platform	Cross-platform
Type	Command
License	coreutils: GPLv3

Syntax

The command syntax is:

head [options] ⟨file_name⟩

By default, head will print the first 10 lines of its input to the standard output.

Option flags

-n ⟨count⟩

--lines=⟨count⟩

The number of lines printed may be changed with a command line option. The following example shows the first 20 lines of filename:

head -n 20 ''filename''

This displays the first 5 lines of all files starting with foo:

head -n 5 ''foo*''

Most versions^{[citation needed]} allow omitting n and instead directly specifying the number: -5. GNU head allows negative arguments for the -n option, meaning to print all but the last - argument value counted - lines of each input file.

-c ⟨bytes⟩

--bytes=⟨bytes⟩

Print first x number of bytes.

Other command

Many early versions of Unix and Plan 9 did not have this command, and documentation and books used sed instead:

sed 5q filename

The example prints every line (implicit) and quits after the fifth.

Equivalently, awk may be used to print the first five lines in a file:

awk 'NR < 6' filename

However, neither sed nor awk were available in early versions of BSD, which were based on Version 6 Unix, and included head.^[1]

Implementations

A head command is also part of ASCII's MSX-DOS2 Tools for MSX-DOS version 2.^[2] The head command has also been ported to the IBM i operating system.^[3]

See also

• tail (Unix)
• dd (Unix)
• List of Unix commands