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%SECTION{summary}%(GNU) info is a hypertext system developed by Richard Stallman to provide an improved method of presenting computer documentation on screen. Info files (usually <filename>.info) can be read with a standalone program named info or with Emacs' "info mode". Emacs' info mode allows "real time" editing of the info file text.

See:

Contents

Getting Started

The standalone info reader program (info) and a collection of .info files are installed by default on most Linux computers.

There are enough commands available in info to overwhelm anyone. Here is a limited subset to get you started with minimal confusion.

  • Start info with info or info <info_file_name> at a command prompt.

  • Read through the entire file in "node order" by pressing the spacebar. Go backwards using <Delete> or <Backspace>. <PgUp> and <PgDn> work within a single node, they will not cross node boundaries.

  • Navigate between links on a page using the <Tab> or <Esc><Tab> keys. Links start with an asterisk, sometimes standalone ("*"), sometimes followed by "Note" ("*Note"). Then:

  • Jump to any linked node by moving the cursor to the line containing the link and pressing <Enter> (<Return>).

  • Info maintains a history of visited nodes. Press "l" (ell) to visit nodes previously visited.

  • Press / to start a full text search, i to start an indexed search (well, a search in the index).

  • Press ? or <ctrl>h to get a summary of all commands. Note that keys are shown using the Emacs convention, i.e., C- means <ctrl> and M- usually means <alt>.

The Info Display

Overview

The info display consists of the following parts:

  • One or more info windows
  • The echo area — a one line window at the bottom of the display

Each info window consists of the following parts:

  • A header line, containing the name of the info file, the name of the current node, and the name of the Next, Previous, and Up (parent) nodes (if they are defined)
  • A text area
  • A mode line (footer) containing status information, see Sample Mode Lines

Sample Display

The following info screen includes two info windows (header, text, mode line) and the echo area after pressing <alt>x. The windows do not look like a typical modern window, as there is no border around them. They are delimited (vertically) by the header and mode lines, and extend the full width of your display (window). These windows were conceived in the era of text based CLIs.

The first window is the beginning of the first node from the info.info file, part of the same sample as is shown in the file format sample at InfoFileFormat#Beginning of a .info File. The second window shows the help available by pressing "?" or <ctrl>h.

The mode lines (start with "-----Info" or "--zz-Info" in this example) are normally displayed in reverse video.

<sample screen>

File: info.info,  Node: Top,  Next: Getting Started,  Up: (dir)

Info: An Introduction
*********************

   The GNU Project distributes most of its on-line manuals in the "Info
format", which you read using an "Info reader".  You are probably using
an Info reader to read this now.

   If you are new to the Info reader and want to learn how to use it,
type the command `h' now.  It brings you to a programmed instruction
sequence.

   To read about expert-level Info commands, type `n' twice.  This
brings you to `Info for Experts', skipping over the `Getting Started'
--zz-Info: (info.info.gz)Top, 24 lines --Top----------------------------
Basic Commands in Info Windows
******************************

C-x 0       Quit this help.
q           Quit Info altogether.
h           Invoke the Info tutorial.

Selecting other nodes:
----------------------
n           Move to the "next" node of this node.
p           Move to the "previous" node of this node.
u           Move "up" from this node.
m           Pick menu item specified by name.
              Picking a menu item causes another node to be selected.
-----Info: *Info Help*, 447 lines --Top---------------------------------
ESC x
</sample screen>

Sample Mode Lines

-----Info: (dir)Top, 40 lines --Top-------------------------------------
            ^^   ^   ^^^        ^^
          (file)Node #lines    where

"where" can be any of Top, Bottom, All, or a percent.

--zz-Info: (emacs)Top, 291 lines --Top-- Subfile: emacs-1.Z-------------

The zz indicates the disk file is compressed, "Subfile" indicates the file has been split into subfiles.

--$--Info: (texinfo)Top, 480 lines --Top-- Subfile: texinfo-1-----------

The $ indicates long lines are truncated instead of wrapped. (Change this with the toggle wrap command: <later>.

-----Info: *Completions*, 7 lines --All---------------------------------

Under some circumstances, info makes an "internal" (virtual) node, indicated by asterisks.

Copying the Content of Info Files

Much of the information on these pages was originally extracted from info info and info info-stnd (/usr/info/info.info.gz and /usr/info/info.info-stnd.gz).

I found it fairly convenient to gunzip the files, copy them into a Nedit file, and then do (semi-manual) reformatting as required, including:

  • converting hard wrapped paragraphs (some indented) to soft wrapped
  • converting Emacs style key notation (C-) to the more common (??) <ctrl> notation

As I extract more data from .info files, I will develop Nedit macros to automate the process.

Aside: Info and Apropos

Aside: I wonder if info is the basis of the apropos command:

`--apropos=STRING'
Specify a string to search in every index of every Info file installed on your system. Info looks up the named STRING in all the indices it can find, prints the results to standard output, and then exits. If you are not sure which Info file explains certain issues, this option is your friend. Note that if your system has a lot of Info files installed, searching all of them might take some time.

You can invoke the apropos command from inside Info; see *Note Searching Commands::.

Other WikiLearn Pages About Info

  • Info: this page, which provides a quick introduction to info
  • Info Command Summary: when you find the need for more commands than are shown on this page (or try "?" from within info)
  • Info File Format: enough information (I hope) to write a .info file in a plain text editor
  • Emacs Info Mode: <later, maybe wink — feel free>

Scope of WikiLearn Info Pages

Initially, these pages address only the things I am most interested in about info:

  • reading info files with the standalone info reader
  • copying the content of info files
  • constructing info files in a plain text editor

Listed below are some info related subjects which are not addressed on these pages: If you are interested, please feel free to create appropriate WikiLearn pages and link to them from this page.

  • Emacs has an info mode which allows both reading and editing of info files.

  • Texinfo is a system that allows production of several different formats (printed document, .info, .html, ???) from a single source file.

Contributors

  • () RandyKramer - 20 Dec 2003
  • If you edit this page: add your name here; move this to the next line; and if you've used a comment marker (your initials in parenthesis), include it before your WikiName.

Revision Comment

%SECTION{last_revision}%
  • %DATE% —

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Topic revision: r4 - 2003-12-21 - RandyKramer
 
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