What does the 'chmod' command do?

The 'chmod' command is specifically used to change the file permissions in a Linux or Unix-like operating system. This command allows users to define who can read, write, or execute a file, thus providing control over access to files and directories. The permissions can be modified for three different user categories: the file owner, the group associated with the file, and others (everyone else).

Using 'chmod', users can set permissions using either symbolic notation (like 'u+x' to add execute permissions for the user) or numeric modes (like '755' to set specific read, write, and execute permissions for the owner, group, and others). By successfully modifying file permissions, 'chmod' plays a crucial role in maintaining security and managing user access to various files in a system.