Info

This guide is meant to show how to navigate info pages using the info command.

What is info?
Most of you may be familiar with the  documentation system. While man is good with quickly looking up items, it lacks structure in linking man pages together. This is where  comes in. Info pages are made using the  tools, and can link with other pages, create menus and ease navigation in general. The next section will look at how info pages are laid out.

Info pages layout
The main info pages are held in. Unlike the man style directory layout, contains what is largely a rather extensive collection of files. These files have the following format:

info file format

is the actual name of the page (example: ). is an optional construct that designates another node level (generally these are referenced to by the toplevel of the info document in question). In order to save space these info pages are compressed using the  compression scheme. Additional info pages can be listed with the  environment variable (usually set through the various  files). To get started, it's important to note the file. This special file is used when info is ran with no parameters. It contains a listing of all info pages available for users to browse. To begin looking at navigating around in info, we'll go ahead and bring it up with no arguments:

Now in the next chapter we'll look at dealing with basic info navigation.

Browsing with menus
Now that info is started, we're given a screen similar to this:

Sample info screen

Right now there are a bunch of entries with an asterisk before them. These are menu items for navigating through different node levels. There are two ways of selecting menus. We'll look at the first now and the other way later. First off, we'll go ahead and look at the  info page. To do so, use the down arrow key until you reach the line for Wget:

Navigating to the wget info menu entry

Once you get to this line, hit the key to select the menu item. This will bring up the info page for  :

The wget info page

Now that we have an info page up, the next section will look at basic navigation.

Basic navigation
In terms of nodes, this is considered the  node for the wget page. Consider the  node to be the same as the table of contents for that particular info page. Now to navigate the actual page itself, you have a couple of different methods. First off is the standard info method. This is using the key to move forward a page and the / keys to move back a page. This is the recommended method as it automatically advances/retreats to the appropriate node in the document. This allows for a somewhat linear browsing for those used to man pages. Another way is through the / keys. These work, but they will not advance/retreat like // will. If you want to skip entire nodes without using //, you can also use the (advance backwards) and  (advance forwards) keys.

As mentioned earlier, there are 2 ways of navigating menus. The other way will now be described here. The numbers  can be used to reference to the first-ninth menu entries in a document. This can be used to quickly peruse through documents. For example, we'll use to reach the   menu entry. So press and it will bring up the   screen:

Resulting Recursive Download screen

Now we're at the  screen. Here is a good time to note a few things. First off the top header section. This header shows the navigation capable from this particular screen. The page indicated by  can be accessed by pressing the  key, and the page indicated by   can be accessed by pressing the  key. Please note that this will only work for the same level. If overused you could round up in totally unrelated content. It's better to use //// to navigate in a linear fashion.

If for some reason you get lost, there are a few ways to get out. First is the key. This will take you straight to the toplevel (table of contents) for the particular info page you're browsing. If you want to return to the last page you looked out, you can do so with the key. If you want to go to the above level, you can do so with the key. Now that you have some idea of navigating a page, the next chapter will look at searching for content.

Navigating to other info pages
Now that you can navigate an individual info page, it's important to look at accessing other info pages. The first obvious way is to go to the info page through the  index listing of info pages. To get to the  index from deep within a document, simply press the  key. From there you can search for the appropriate page you want. However, if you know the actual page, there is an easier way through the  command. To go to an info page by name, type to bring up the prompt and enter the name of the page in parentheses:

Going to an info page by name

This will bring up the libc page as shown here:

Result of the Goto node command

Now that we know how to go to info pages by name, the next section will look at searching for pieces of information using the info page's index.

Searching using an index
In this example we'll see how to lookup the  function of the c library using the   info page's index. You should still be at the libc info page from the last section, and if not, use the Goto node command to do so. To utilize the index search, hit the key to bring up the prompt, then enter your search term. We'll do so for  below:

Entering an index search query

After pressing enter upon completion of our query, we're brought to the  definition for  :

Result of the index search query

We've now successfully performed a search using the  info page index. However, sometimes what we want is in the page itself. The next section will look at performing searches within the page.

Searching using the search command
Starting from the previous location at the  node, we'll look at searching for the   variation of the   function. To perform a search, press the key to bring up the search prompt, and then enter the query (sprintf in this case):

Entering a search query

Hit and it will show the result of the query:

Result of the search query

And we have the function we need.

Conclusion
This concludes the overview of using info to view info pages. As always comments are both welcome and appreciated.

Additional Program Resources
In order to make things easier for those that wish to browse info pages through a more friendly graphical interface, the following are available:


 * - Convert info pages to a browse-able HTML format
 * -  based info viewer
 * - a  based info browser
 * - a  based info browser

The  browser   also allows you to browse info pages through the   URI.