Everything is a file in a Unix computer, including a device. Devices in the /dev directory differ in that they have major and minor device numbers to tell their drivers how to use them. |
File kinds are read from the directory "ls -l" command which reveals "permissions" numerically like 755, 644, 600 representing THREE octal digits "owner", "group" and "others". Each octal digit is the sum of Read = 4, Write = 2, Execute =1. From "ls -l" we see -rwx------ for a 700 file (regular file) .. Expect a "drwxr-xr-x" to be an example of a directory (755). Block and character devices start with b or c, and symbolic links are "l". Example. |
Another property pair for files is ownership, "owner" and "group" which usually derive from the users "passwd file" values .. later. Or man passwd. |
Common files which we deal directly include text, scripts and HTML files. The command "file filename" offers clues as t file types. Oh yes, xROFF are commonly nroff or troff files comprising the "manual" pages. |