man | System Help

man (short for “manual”) is a traditional form of online documentation in Unix and Linux operating systems. Specially formatted files, “man pages”, are written for most commands and distributed with the software. Running man somecommand will display the man page for (naturally) the command or program somecommand.

Because there are so many of them, man pages are grouped into enumerated sections. This system has been around so long that you will often see commands, programs, and even programming library functions referred to with their man section number. For instance, you might see man(1). This tells you that man is documented in section 1 (user commands); you can specify that you want the section 1 man page for “man” with the command man 1 man. Specifying the section that man should look in is useful in the case of multiple items with the same name.

Table 2-1. Man Page Sections

Section 1user commands (intro only)
Section 2system calls
Section 3C library calls
Section 4devices (e.g., hd, sd)
Section 5file formats and protocols (e.g., wtmp, /etc/passwd, nfs)
Section 6games (intro only)
Section 7conventions, macro packages, etc. (e.g., nroff, ascii)
Section 8system administration (intro only)

In addition to man(1), there are the commands whatis(1) and apropos(1), whose shared purpose is to make it easier to find information in the man system. whatis gives a very brief description of system commands, somewhat in the style of a pocket command reference. apropos is used to search for a man page containing a given keyword.

See their man pages for details.

The /usr/doc Directory

The source for most packages that we build comes with some sort of documentation. README files, usage instructions, license files… any sort of documentation that comes with the source is included and installed on your system in the /usr/doc directory.

If man pages don’t provide enough information, /usr/doc should be your next stop.

HOWTOs and mini-HOWTOs

It is the true spirit of community that brings you the HOWTO/mini-HOWTO collection. These files are exactly what they sound like– documents describing how to do stuff. If you install the HOWTO collection package, HOWTOs will be installed to /usr/doc/Linux-HOWTOs and the mini-HOWTOs to /usr/doc/Linux-mini-HOWTOs.

Also included in the same package is a collection of FAQs (Frequently Asked Questions lists– with answers) which are installed to the same place.

These files are well worth reading whenever you’re not quite sure how to proceed with something. An amazing range of topics are covered in sometimes surprising detail.

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