What command would you use to change file permissions in Linux?

The command used to change file permissions in Linux is chmod. This utility allows you to define who can read, write, or execute a file by modifying the permission settings associated with that file.

In Linux, file permissions are represented in three areas: owner permissions, group permissions, and others. The chmod command can be utilized with symbolic or numeric notation to conveniently set these permissions. For example, using "chmod 755 filename" would set read, write, and execute permissions for the owner, and read and execute permissions for the group and others.

The other commands, while related to file management and permissions, serve different purposes. The chown command is used to change the ownership of a file or directory. The chgrp command changes the group associated with a file or directory. The option "fileperm" does not exist as a standard command in Linux for changing file permissions, making it irrelevant in this context. Thus, the solution clearly points to chmod as the command specifically designed for altering file permissions.