What is the purpose of the 'chmod' command?

The 'chmod' command is specifically designed to change the permissions of a file or directory in a Linux operating system. In Linux, every file and directory has associated permission settings that determine who can read, write, or execute them. The 'chmod' command allows users to modify these permissions using symbolic or numeric notation.

For example, when using symbolic notation, you might assign read, write, or execute permissions to the owner, group, or others. Numeric notation allows you to set permissions by specifying a three-digit code, where each digit represents the permissions for the owner, group, and others respectively. This flexibility makes 'chmod' a crucial tool for managing security and access control in a multi-user environment.

The other options address different file management functions that are outside the scope of what 'chmod' does. Changing the owner or group of a file involves commands like 'chown' and 'chgrp', while copying files is performed using the 'cp' command. Each of these commands has its specific purpose and functionality, distinct from that of 'chmod'.