info is a GNU help utility that allows users to browse and navigate a hyperlinked hierarchical structure of info pages. Individual pages are crafted so that sub-topics or related topics can be accessed from within the info utility.

Whereas the man system is a collection of individual man pages with the possibility of a particular topic having separate man pages depending on specific information desired, the info system is a database of information files arranged in a tree like structures.

The primary database for GNU/Linux system and utilities is "info" and covers most topics. If a system has additional products or utilities that that are not part of the standard configuration, a separate database or tree may be available on that topic. For example, our system provides a separate info tree for Emacs editor.

When looking up a topic info may enter the tree at the top, or at a node at some position below the top with the possibility of moving up to a more general discussion, down to a more detailed focus on some aspect of the topic, or side to side (using next and previous) to topics related to the current topic.

Go to the terminal and run info on the GNU core utilities.

% info coreutils.info

You will see :

File: coreutils.info, Node: Top, Next: Introduction, Up: (dir) GNU Coreutils ************* This manual documents version 8.23 of the GNU core utilities, including the standard programs for text and file manipulation. Copyright © 1994-2014 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”. * Menu: * Introduction:: Caveats, overview, and authors * Common options:: Common options * Output of entire files:: cat tac nl od base64 * Formatting file contents:: fmt pr fold * Output of parts of files:: head tail split csplit * Summarizing files:: wc sum cksum md5sum sha1sum sha2 * Operating on sorted files:: sort shuf uniq comm ptx tsort * Operating on fields:: cut paste join # several more pages of information.

Use the cursor to scroll up and down to see the whole page. Use q if you want to quit the info help.

Examining the display, the first line should be :

File: coreutils.info,  Node: Top,  Next: Introduction,  Up: (dir)

This line notes the info file you are viewing, File: coreutils.info, your position in the tree structure, Node: Top, of the coreutils.info tree, the next node in the info tree structure, Next: Introduction, and the parent node of this entry, Up: (dir). As you move down the tree, you may also be presented with a Prev: some topic.

Depending on where you are in the information tree, some of these may be missing.

There are several ways to traverse linked pages.

If Next:, Prev:, or Up: are listed at the top of the page, you can use [n] to follow the Next link, [p] to follow the Prev: link or U to go up a level in the info tree.

This section may be followed by the menu. A menu consists of a set of lines starting with an ansterick, *, a topic title, and possibly additional descriptive text.

For example, scroll down to :

* Output of parts of files::     head tail split csplit

Use [u] to return to the starting page.

The navigation commands for info are fairly unique to info but do borrow some from emacs. Typing [h] on any page will bring up a quick guide of available commands. Use [x] to exit the quick help.

Note, on our system, the quick help lists [H] as a way to run the info tutorial. This does not exits and the command will bring up a copy of the info man page listing its options. Lectures