Which command is used to change file permissions in Linux?

The command used to change file permissions in Linux is chmod. This stands for "change mode" and allows users to modify the read, write, and execute permissions of files and directories for the owner, group, and others. The syntax for chmod can involve using symbolic notation (like u+x to add execute permission for the user) or octal notation (like 755 to set specific permission levels).

Using chmod is crucial for managing security and access control on a Linux system, ensuring that only authorized users can view or modify files as needed.

In contrast, chown is used to change the owner and group of a file, cp is utilized for copying files, and touch is typically employed to change file timestamps or create empty files. These commands serve different purposes unrelated to modifying file permissions.