What does the 'chmod' command do?

The 'chmod' command is used to change file permissions in a Linux operating system. File permissions define who can read, write, or execute a file, and are essential for maintaining security and accessibility within the system. Using 'chmod', a user can grant or restrict access to files or directories for various user classes: the owner of the file, members of the file's group, and all other users. The command can be used in symbolic form (like 'rwx' for read, write, and execute) or numeric form (such as 755 or 644) to set the desired permissions accordingly. This capability is a fundamental part of managing the security and functionality of files within Linux systems.