What does 'chmod' do in Linux?

The command 'chmod' in Linux is specifically designed to change the permissions associated with files and directories. Permissions determine who can read, write, or execute a file. The command uses a specific syntax that allows users to grant or deny permissions for the owner of the file, members of the owner's group, and other users.

When you use 'chmod', you can specify permissions in either symbolic form (using letters to represent user categories and permissions) or numeric form (using octal numbers to set specific permission levels). For instance, using 'chmod 755 filename' would set the permissions so that the owner can read, write, and execute, while the group and others can read and execute but not write.

This means that the function of 'chmod' is central to managing access control in a Linux environment, ensuring that only authorized users can manipulate files in ways that they should be allowed to. Understanding how to effectively use 'chmod' is an essential skill for managing file security and permissions in Linux systems.