4.2. Accessing Online Documentation
A fully loaded Fedora system includes over 4,700 programs, plus programming interfaces, data files, and graphical tools. To help you learn your way around, over 12,000 files of online documentation are available, with additional documentation available through the Web. Knowing how to access and knowledgeably navigate through this documentation is essential to getting the most out of your Fedora system.
4.2.1. How Do I Do That?
There are five main types of documentation available:
18.104.22.168. Using manpages
Fedora continues the Unix tradition of providing an online version of what were originally loose-leaf printed manuals. These manuals cover the commands, programming interfaces, and data formats used by the system.
The pages are arranged into sections according to the original binders, using the section numbers described in Table 4-2. The section numbers are used to distinguish different manpages with the same name, such as the manpage for the uname system call (found in section 2) and the uname command (found in section 1). In some cases, a letter or two may be appended to a section number to indicate a subsection (such as 3pm, the manual section containing Perl module library functions).
To view the manpage for a particular command, such as ls:
$ man ls
The output will appear as shown in Figure 4-1. You can use the up and down arrow keys and the Page Up/Page Down keys to scroll through the text, or q to quit. You can also type /, enter some text, and press Enter to search for that text within the document; type n (lowercase n, for next) to search again. ? and N (uppercase N) can be used in the same way to search backwards.
Figure 4-1. Online display of a manpage
To request a manpage from a specific section of the manual, give the section as the first argument and the name of the manpage as the second argument:
$ man 2 uname
If you don't specify the section, the first section containing a page with the requested name is usedand since there is a uname page in section 1, you won't see the page from section 2 unless you specifically ask for it.
22.214.171.124. Finding a manpage
The -k argument of man is used to produce a list of all of the pages that contain a specific keyword in their short descriptions. For example, if you wanted to see all of the manpages that contained the word calendar in their summary:
$ man -k calendar Date::Calc (3pm) - Gregorian calendar date calculations Date::Calendar (3pm) - Calendar objects for different holiday schemes Date::Calendar::Profiles (3pm) - Some sample profiles for Date::Calendar and Date::Calendar::Year Date::Calendar::Year (3pm) - Implements embedded year objects for Date::Calendar cal (1) - displays a calendar
Note that the section number is in parentheses. If you were looking for a calendar command, you could ignore the results from section 3 of the manual (library functions), which leaves just one possibility: the cal command. You could then get more information about that command to see if it will do what you need:
$ man cal
$ whatis uname uname (1) - print system information uname (2) - get name and information about current kernel
In this case, you can see that there is a page for uname in section 1 and 2 of the manual.
126.96.36.199. Reading info documents
The GNU project supplies most of its documentation in info documents rather than manpages. info documents are a unique form of hypertext and are read with a reader program named, not surprisingly, info:
$ info ls
info has many features and can be a bit overwhelming. Each document consists of nodes (analogous to web pages) that are linked together using menu options. The keys listed in Table 4-3 are sufficient for basic navigation.
To take a guided tour of info, type:
$ info info
188.8.131.52. Viewing GNOME guides and KDE manuals
To access these guides, just press F1 in a GNOME or KDE application. Alternately, select the SystemHelp (GNOME) or Help (KDE) menu options from the panel bar. The GNOME menu is connected to the GNOME documentation, and the KDE menu is connected to the KDE documentation. You can access the documentation for the other desktop environment from a command prompt; for GNOME documentation, use either of these commands:
$ gnome-help $ yelp
184.108.40.206. Accessing HOWTOs and guides
The Linux Documentation Project (TLDP) maintains a very helpful set of documents called HOWTOs, each of which describes the procedure to accomplish a specific task. They also publish some book-length guides. Most of these documents have been translated into multiple languages. However, these documents are generic and do not reflect the default configuration and packaging of Fedora.
The TLDP documentation can be found on the Web at http://www.tldp.org/. TLDP also publishes FAQs and maintains links to online versions of the manpages and free Linux magazines.
220.127.116.11. Viewing text files distributed with applications
Most open source software packages include a small number of text files written by the programmers, which include licensing information, change histories, errata and bug lists, and release notes. In Fedora these miscellaneous documents are placed in /usr/share/doc and are organized in directories by package name and version. For example, the notes for dia (a diagram-drawing application) are available in /usr/share/doc/dia-0.95.
I find that the easiest way to view these documents is to use a web browser, which enables you to navigate among directories and view documents by simply clicking on them. To do this, just open the Firefox web browser and enter /usr/share/doc as the location.
To view these files from the shell prompt, change to the directory you wish to view, and then use ls to list names of the files and less to view the contents of any text files that interest you. For example, here are the steps you might take to view the dia text files:
$ cd /usr/share/doc $ ls -d dia* dia-0.95 dialog-1.0.20050306 $ cd dia-0.95 $ ls -l total 724 -rw-r--r-- 1 root root 1578 Aug 16 2004 AUTHORS -rw-r--r-- 1 root root 574015 Aug 17 2004 ChangeLog -rw-r--r-- 1 root root 17992 Mar 12 2004 COPYING -rw-r--r-- 1 root root 11364 Aug 16 2004 custom-shapes -rw-r--r-- 1 root root 1620 Aug 16 2004 diagram.dtd -rw-r--r-- 1 root root 3927 Aug 16 2004 INSTALL -rw-r--r-- 1 root root 4955 Aug 16 2004 KNOWN_BUGS -rw-r--r-- 1 root root 21535 Aug 17 2004 NEWS -rw-r--r-- 1 root root 3444 Aug 16 2004 README drwxr-xr-x 2 root root 4096 Sep 27 01:13 samples -rw-r--r-- 1 root root 2324 Aug 16 2004 shape.dtd -rw-r--r-- 1 root root 501 Aug 16 2004 sheet.dtd -rw-r--r-- 1 root root 1379 Aug 19 2004 THANKS -rw-r--r-- 1 root root 2545 Aug 16 2004 TODO $ less KNOWN_BUGS
The less command will enable you to scroll through the specified file (KNOWN_BUGS) in the same way that you would move through a manpage, using the arrow keys and Page Up/Page Down keys to scroll and q to quit.
Note that this directory also contains a sample directory, which includes some sample files for use with the dia program.
4.2.2. What About...
18.104.22.168. ...printing a manpage?
$ man -t ls | lpr
22.214.171.124. ...making a PDF or HTML version of a manpage?
It's easy to convert manpages into PDF or HTML formats.
$ man -t ls | ps2pdf - ls_man_page.pdf
The commands to convert a manpage to HTML are more complex:
$ zcat $(man --path ls) | man2html | tail +3 > ls_man_page.html
4.2.3. Where Can I Learn More?
Other sources of information about Fedora and Linux: