Editing Less (Unix) (section)

==Usage==
{{mono|less}} can be invoked with options to change its behaviour, for example, the number of lines to display on the screen. A few options vary depending on the operating system. While {{mono|less}} is displaying the file, various commands can be used to navigate through the file. These commands are based on those used by both {{mono|more}} and {{mono|[[Vi (text editor)|vi]]}}. It is also possible to search for character patterns in the file.

By default, {{mono|less}} displays the contents of the file to the [[standard output]] (one screen at a time). If the file name argument is omitted, it displays the contents from [[standard input]] (usually the output of another command through a [[Pipeline (Unix)|pipe]]). If the output is redirected to anything other than a [[Computer terminal|terminal]], for example a pipe to another command, {{mono|less}} behaves like {{mono|[[cat (Unix)|cat]]}}.

The "lesspipe" extension can automatically determine file types such as [[PDF]], multimedia, and [[compressed archive]]s, and automatically determines which program to launch display the file's information with, such as text from a PDF file, metadata of photos, lists of files in a compressed archive, and content of a single file in a compressed archive.<ref>{{cite web |url=https://manpages.debian.org/bullseye/less/lesspipe.1.en.html |title = lesspipe(1) — less — Debian bullseye — Debian Manpages}}</ref><ref>{{cite web |url=https://man.archlinux.org/man/lesspipe.1 |title = lesspipe(1) — Arch manual pages}}</ref>

The command-[[syntax]] is:

 less [options] [file_name]...

===Frequently used options===
*<code>-g</code>: Highlight just the current match of any searched string.
*<code>-i</code>: Search case-insensitively.
*<code>-m</code>: Show more detailed prompt, including file position.
*<code>-N</code>: Show line numbers (useful for viewing [[source code]]).
*<code>-x3</code>: Set tabstops (the number of columns per hard tab character) to the specified number (3, in this example) (useful for viewing [[source code]]).
*<code>-S</code>: Disable line wrapping ("chop long lines").  Long lines can be seen by side-scrolling.
*<code>-X</code>: Leave file contents on screen when less exits.
*<code>-?</code>: Show help.
*<code>--follow-name</code>: Follow mode, for log files that get replaced while being viewed.

===Frequently used commands===

{| class="wikitable" border="1"
|-
! Key
! Command
|-
! {{Key press|Space bar}}
| Next Page
|-
! {{Key press|d}}
| Next half Page
|-
! {{Key press|b}}
| Previous Page
|-
! {{Key press|u}}
| Previous half Page
|-
! {{Key press|v}}
| Edit Content
|-
! {{Key press|j}} <span style="font-weight: normal;">or</span> {{Key press|Enter}}
| Next Line
|-
! {{Key press|k}}
| Previous Line
|-
! {{Key press|Home}}
| Top of file
|-
! {{Key press|End}}
| End of file
|-
! {{Key press|F}}
| Follow Mode (for expanding logs or pipes). Interrupt (or from v581 {{Key press|Ctrl|X}}<ref>{{cite web|url=http://www.greenwoodsoftware.com/less/news.581.html|title=Less version 581|publisher=Greenwood Software|date=7 April 2021|access-date=31 July 2023}}</ref>) to abort.
|-
! {{Key press|g}} <span style="font-weight: normal;">or</span> {{Key press|<}}
| First Line
|-
! {{Key press|G}} <span style="font-weight: normal;">or</span> {{Key press|>}}
| Last Line
|-
! <code>{{angbr|n}}</code>{{Key press|G}}
| Line <code>{{angbr|n}}</code>
|-
! {{Key press|/}}<code>{{angbr|text}}</code>
| Forward Search for <code>{{angbr|text}}</code>. Text is interpreted as a [[Regular expression|regex]].
|-
! {{Key press|?}}<code>{{angbr|text}}</code>
| Backward Search like {{Key press|/}}
|-
! {{Key press|&}}<code>{{angbr|text}}</code>
| [[grep]] like filter
|-
! {{Key press|n}}
| Next Search Match
|-
! {{Key press|N}}
| Previous Search Match
|-
! {{Key press|Esc}}{{Key press|u}}
| Turn off Match Highlighting (see <code>-g</code> command line option)
|-
! {{Key press|-}}<code>{{angbr|c}}</code>
| Toggle option <code>{{angbr|c}}</code>, e.g., {{Key press|-}}{{Key press|i}} toggles option to match case in searches
|-
! {{Key press|m}}<code>{{angbr|c}}</code>
| Set Mark <code>{{angbr|c}}</code>
|-
! {{Key press|'}}<code>{{angbr|c}}</code>
| Go to Mark <code>{{angbr|c}}</code>
|-
! {{Key press|{{=}}}} <span style="font-weight: normal;">or</span> {{Key press|Ctrl|G}}
| File information
|-
! {{Key press|:}}{{Key press|n}}
| Next file
|-
! {{Key press|:}}{{Key press|p}}
| Previous file
|-
! {{Key press|h}}
| Help. This is presented with <code>less</code>, {{Key press|q}} to quit.
|-
! {{Key press|q}}
| Quit
|}