In Unix operating systems, the chmod command is used to change the access mode of a file. The name is an abbreviation for change mode. It states that each file and directory has a set of permissions that control permissions, such as who can read, write, or execute the file. Permissions are divided into three categories: read, write and execute at the same time, represented by "r", "w" and "x". These letters are combined to form a set of user-specific permissions.
The `chmod` command is used to modify this permission so that it can grant or restrict access to directories and files. Let’s take a look at the syntax and options of “chmod” command in Linux operating system.
syntax:
chmod [options] [mode] [filename]