Gentoo Info GuideMost of you may be familiar with the man documentation system. While man is good with quickly looking up items, it lacks structure in linking man pages together. This is where info comes in. Info pages are made using the texinfo 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. The main info pages are held in /usr/share/info. Unlike the man style directory layout, /usr/share/info contains what is largely a rather extensive collection of files. These files have the following format:
pagename is the actual name of the page (example: wget). [-node] 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 gzip compression scheme. Additional info pages can be listed with the INFOPATH environment variable (usually set through the various /etc/env.d/ files). To get started, it's important to note the /usr/share/info/dir 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. Now that info is started, we're given a screen similar to this:
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 wget info page. To do so, use the down arrow key until you reach the area indicated by the blue highlighting:
Once you get to this area, hit the ENTER key to select the menu item. This will bring up the info page for wget:
Now that we have an info page up, the next section will look at basic navigation. In terms of nodes, this is considered the Top node for the wget page. Consider the Top 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 SPACE key to move forward a page and the BACKSPACE/DELETE 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 PAGE UP/PAGE DOWN keys. These work, but they will not advance/retreat like SPACE/BACKSPACE/DELETE will. If you want to skip entire nodes without using SPACE/BACKSPACE/DELETE, 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 1-9 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 3 to reach the Recursive Download menu entry. So press 3 and it will bring up the Recursive Download screen:
Now we're at the Recursive Download 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 Next: can be accessed by pressing the n key, and the page indicated by Prev: can be accessed by pressing the p 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 SPACE/BACKSPACE/DELETE/[/] to navigate in a linear fashion. If for some reason you get lost, there are a few ways to get out. First is the t 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 l key. If you want to go to the above level, you can do so with the u 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 dir index listing of info pages. To get to the dir index from deep within a document, simply press the d 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 Goto node (g key) command. To go to an info page by name, type g to bring up the prompt and enter the name of the page in parentheses:
This will bring up the libc page as shown here:
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. In this example we'll see how to lookup the printf function of the c library using the libc 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 i key to bring up the prompt, then enter your search term. We'll do so for printf below:
After pressing enter upon completion of our query, we're brought to the libc definition for printf:
We've now successfully performed a search using the libc 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 Formatted Output Functions node, we'll look at searching for the sprintf variation of the printf function. To perform a search, press the s key to bring up the search prompt, and then enter the query (sprintf in this case):
Hit ENTER and it will show the result of the query:
And we have the function we need. This concludes the overview of using info to view info pages. As always comments are both welcome and appreciated. Clicking on the my name (Chris White) on the right side will send me an email. In order to make things easier for those that wish to browse info pages through a more friendly graphical interface, the following are available:
The KDE browser Konqueror also allows you to browse info pages through the info: URI. The contents of this document are licensed under the Creative Commons - Attribution / Share Alike license. |
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