What is the purpose of the command 'chmod' in Linux?

The command 'chmod' in Linux is specifically designed to change file permissions. In a Linux environment, every file and directory has a set of permissions that define who can read, write, or execute it. The 'chmod' command allows users to modify these permissions by using symbolic or numeric modes.

When you use 'chmod', you can specify different access levels for the owner of the file, the group, and others (everyone else). This is crucial for maintaining security and controlling access within a multi-user system. For instance, you could allow a script to be executable only by its owner, while others may only have permission to read it, thus ensuring that sensitive or critical files are protected from unauthorized access.

Understanding 'chmod' and how to manipulate permissions is an essential skill for managing files and maintaining security in a Linux operating system. This is key in tasks ranging from simple file management to complex system administration activities.