Just as man is the original help system developed with and for the original AT&T Unix system, info is the help system developed for GNU/Linux systems.
In the business world you may find that many commerical Unix systems will not recognize the info command. However, as more GNU utilities get ported to the commercial environment, info tends to follow as it often offers better help pages for the GNU utilities. So, it is best to be reasonably familiar with both.
Whereas the man system is a collection of individual man pages with the possibility of a particular topic having separate man pages classified in different sections, the info system is a database of information files arranged in a tree like structures.
The primary database for GNU/Linux system and utilitles 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 separate info trees for ada, emac, the gnu news viewer, and other topics.
When looking up a topic info may enter the tree at the top, or at a node at some postition 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 info.
% info info
You will see :
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. There are two primary Info readers: `info', a stand-alone program designed just to read Info files, and the `info' package in GNU Emacs, a general-purpose editor. At present, only the Emacs reader supports using a mouse. 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' chapter. * Menu: * Getting Started:: Getting started using an Info reader. * Expert Info:: Info commands for experts. * Creating an Info File:: How to make your own Info file. * Index:: An index of topics, commands, and variables. |
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: info.info, Node: Top, Next: Getting Started, Up: (dir)
This line notes the info file you are viewing (File: info.info), your position in the tree structure (Node: Top), any related topics (Next: Getting Started), and the parent node of this entry (Up: (dir)).
In this case, [up] will bring you to the overall controlling node for the info database. If you choose to go to the next topic by pressing n, the top line will also display a previous topic which you may return to to by pressing p.
Under the top line, you see the topic title for the current page and several paragraphs describing the particular topic.
This section may be followed by the menu. A menu consists of a set of lines consisting of an *, a topic title and possibly additional descriptive text. If you place the cursor on one of these lines and press [enter], the page on that topic will be displayed. press u (up) to return to the parent node. You can also press l (last) to return to the last page viewed.
For example, scroll down to the "Getting Started" topic and press [enter]. The following will be displayed :
File: info.info, Node: Getting Started, Next: Expert Info, Prev: Top, Up: Top 1 Getting Started ***************** This first part of this Info manual describes how to get around inside of Info. The second part of the manual describes various advanced Info commands, and how to write an Info as distinct from a Texinfo file. The third part briefly explains how to generate Info files from Texinfo files. * Menu: * Help-Small-Screen:: Starting Info on a Small Screen. * Help:: How to use Info. * Help-P:: Returning to the Previous node. * Help-^L:: The Space, DEL, B and ^L commands. * Help-Inv:: Invisible text in Emacs Info. * Help-M:: Menus. * Help-Xref:: Following cross-references. * Help-Int:: Some intermediate Info commands. * Help-Q:: Quitting Info. |
Notice that you are still in the info.info file and you are in the "Getting Started" node, the next topic is "Expert Info", both the the previous and top nodes are "Top".
Take some time and read the "Getting Started" Node and its sub-nodes.
info is a very powerful help system, but don't panic. Most of the time, the help page retrieved will provide the information you are looking for. Also, check the man pages for other information.