Head (Unix)

Template:More citations needed Template:Short description Template:Lowercase {{#invoke:Infobox|infobox}}Template:Template other{{#invoke:Check for unknown parameters | check | showblankpositional=1 | unknown = Template:Main other | preview = Page using Template:Infobox software with unknown parameter "_VALUE_"|ignoreblank=y | AsOf | author | background | bodystyle | caption | collapsetext | collapsible | developer | discontinued | engine | engines | genre | included with | language | language count | language footnote | latest preview date | latest preview version | latest release date | latest release version | latest_preview_date | latest_preview_version | latest_release_date | latest_release_version | licence | license | logo | logo alt | logo caption | logo upright | logo size | logo title | logo_alt | logo_caption | logo_upright | logo_size | logo_title | middleware | module | name | operating system | operating_system | other_names | platform | programming language | programming_language | released | replaced_by | replaces | repo | screenshot | screenshot alt | screenshot upright | screenshot size | screenshot title | screenshot_alt | screenshot_upright | screenshot_size | screenshot_title | service_name | size | standard | title | ver layout | website | qid }}Template:Main other <syntaxhighlight lang="text" class="" style="" inline="1">head</syntaxhighlight> is a program on Unix and Unix-like operating systems used to display the beginning of a text file or piped data.

SyntaxEdit

The command syntax is:

head [options] Template:Angbr

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

Option flagsEdit

Template:Glossary Template:Term Template:Term Template:Defn Template:Term Template:Term Template:Defn Template:Glossary end

Other commandEdit

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.<ref>Template:Cite journal</ref>

ImplementationsEdit

A head command is also part of ASCII's MSX-DOS2 Tools for MSX-DOS version 2.<ref>MSX-DOS2 Tools User's Manual by ASCII Corporation</ref> The Template:Mono command has also been ported to the IBM i operating system.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

ReferencesEdit

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External linksEdit

Template:Sister project

head manual page from GNU coreutils.
FreeBSD documentation for head

Template:Unix commands Template:Core Utilities commands