Book: LPI Linux Certification in a Nutshell Section: Chapter 10. Exam 101 Highlighter's Index
### 10.4 Documentation (Topic 1.8) #### 10.4.1 Objective 1: Use and Manage Local System Documentation ##### 10.4.1.1 Text and paging In the context of Linux systems, plain text means files or streams of both printable characters and control characters, using a standard encoding scheme such as ASCII. Differentiating text from nontext isn't obvious, but the file command examines a file given as its argument and offers a response that indicates the file type. A pager is a program intended to offer a quick and simple interface for viewing text files, one screen at a time. more is a popular pager available on most Unix systems. less is a full-featured text pager, which emulates more and offers significant advantages. Common less commands are listed in Table 10-6.

##### Table 10-6. Common less Commands

less Command | Description
--- | ---
Space | Scroll forward one screen.
`D` | Scroll forward one-half screen.
Return | Scroll forward one line.
`B` | Scroll backward one screen.
`U` | Scroll backward one-half screen.
`Y` | Scroll backward one line.
`g` | Go to the beginning of the text (could be slow with large amounts of text).
`G` | Go to the end of the text (could be slow with large amounts of text).
`/`pattern | Search forward for pattern, which can be a regular expression.
`?`pattern | Search backward for pattern, which can be a regular expression.
`H` | Display a help screen.
`:n` | Display next file from command line (two-character command).
`:p` | Display previous file from command line (two-character command).
A pager such as less is used by the man facility. ##### 10.4.1.2 The man facility A manpage exists for most commands and is viewed using man: man [section] command Format and display manpages from the manual section based on the topic of command using a pager. Manpages are usually found in the /usr/man directory, but they can also be found elsewhere in the filesystem. The manpage location can be found in /etc/man.config, along with the paging program to use and other information about the manpages. ##### 10.4.1.3 /usr/doc Many documents for Linux systems are available in /usr/doc . Included here are package-related documents, FAQs, HOWTOs, and so on. ##### 10.4.1.4 The info facility The Free Software Foundation provides the info documentation format. GNU software comes with info documentation. The documentation is viewed with the info command, which displays a full-screen editor-like paging system. Common info commands are listed in Table 10-7.

##### Table 10-7. Common info Commands

info Command | Description
--- | ---
Tab | Move among hypertext links.
Enter | Follow hypertext links.
`d` | Return to the top (directory node) of the menu.
`?` | List all info commands.
`p` and `n` | Move to previous and next pages, respectively.
`u` | Move up one level in the Texinfo hierarchy.
`q` | Terminate the system.
`h` | Give a primer for first-time users.
`/`string | Enter a string.
`/`pattern | Search forward for pattern, which can be a regular expression.
#### 10.4.2 Objective 2: Find Linux Documentationon the Internet ##### 10.4.2.1 Linux Documentation Project A loosely knit team of writers, proofreaders, and editors who work together to create the definitive set of documentation for Linux. The Linux Documentation Project can be found online at http://www.linuxdoc.org/. The LDP has a wide range of documents, from complete books to personal accounts of problem-solving techniques. ##### 10.4.2.2 Other sources Many Usenet newsgroups, such as comp.os.linux, comp.os.linux.advocacy, comp.os.linux.development, and others, are dedicated to Linux. Mailing lists offered by many Linux groups serve to keep members informed through email distribution of information. #### 10.4.3 Objective 3: Write System Documentation System manpages are an excellent place to create local documentation. Raw man files are usually processed using nroff for display purposes. You can use this format or simply create a text file and store it in the appropriate cat directory. Local manpages will probably go in /usr/local/man.