Command Manuals

It is a good habit to understand commands by looking into their manual page, e.g. find out the usage and options available for listing a directory,$ man pow.The include<math.h> tell us the header file needed when compiling

The Link with -lmtell us we need "-lm" when compiling program with math functions

Well, what does the number 3 mean in POW(3)?

Man pages are divided into sections. The number corresponds to what section of the manual that page is from; 1 is Executable programs or shell commands, while 3 is Library calls. The man page for man itself (man man) explains it and lists the standard ones:There are certain terms that have different pages in different sections (e.g.printfas a command appears in section 1, as a library call appears in section 3); in cases like that you can pass the section number tomanbefore the page name to choose which one you want, or useman -ato show every matching page in a row:

$ man 1 printf
$ man 3 printf
$ man -a printf