Which command can be used to change file permissions in Linux?

The command used to change file permissions in Linux is chmod, which stands for "change mode." This command allows users to modify the read, write, and execute permissions for the owner of the file, the group associated with the file, and others (anyone else who has access).

When using chmod, you can specify the desired permissions using either symbolic notation (like u+r, g-w, o+x for user, group, and others respectively) or numeric notation (like 755 or 644), providing flexibility in how permissions are set.

This command is fundamental for managing access control, ensuring that you can protect files and directories from unauthorized access while granting the necessary permissions to users who require them.

Other options listed are not valid commands in Linux for changing file permissions, thus reinforcing that chmod is the only correct choice in this context.