The chgrp command can be used to change the group associated with a specified file or directory. This command is especially useful when managing multiple files and directories, as it allows you to quickly assign or reassign groups to multiple files and directories at once.
chgrp <group_name> [file_name]
Once the command has been executed, the group associated with the specified file should be changed to the group you have specified. This should be reflected in the file or directory listing command (e.g. ls): the group associated with the file should now be the group specified.