head (Unix)

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head

GPLv3

head is a

data.

Syntax

The command syntax is:

head [options] ⟨file_name⟩

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

.

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 quit after the fifth.

Equivalently,

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

, 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

References

External links

The Wikibook Guide to Unix has a page on the topic of: Commands

• head manual page from
  coreutils
  .
• FreeBSD documentation for head