Something about Man

man1: User programs. Manual pages that describe publicly accessible commands are contained in this chapter. Most program documentation that a user will need to use is located here.

man2: System calls. This section describes all of the system calls (requests for the kernel to perform operations).

man3: Library functions and subroutines. Section 3 describes program library routines that are not direct calls to kernel services. This and chapter 2 are only really of interest to programmers.

man4: Special files. Section 4 describes the special files, related driver functions, and networking support available in the system. Typically, this includes the device files found in /dev and the kernel interface to networking protocol support.

man5: File formats. The formats for many data files are documented in the section 5. This includes various include files, program output files, and system files.

man6: Games. This chapter documents games, demos, and generally trivial programs. Different people have various notions about how essential this is.

man7: Miscellaneous. Manual pages that are difficult to classify are designated as being section 7. The troff and other text processing macro packages are found here.

man8: System administration Programs used by system administrators for system operation and maintenance are documented here. Some of these programs are also occasionally useful for normal users.