Deciphering the security characters will take a bit more work. First, you must think of those nine characters as three sets of three characters (see bottom right). Each of the three "rwx" characters refers to a different operation you can perform on the file. The 'r' means you can "read" the file's contents. The 'w' means you can "write", or modify, the file's contents. The 'x' means you can "execute" the file. This permission is given only if the file is a program. If any of the "rwx" characters is replaced by a '-', then that permission has been revoked. For example, the owner's permissions for our three primate files are "rw-". This means that the owner of the file ("keeper", i.e. you) can "read" it (look at its contents) and "write" it (modify its contents). You cannot execute it because it is not a program; it is a text file. Members of the group "prim" can only read the files ("r--"). We want to change the second permission character from '-' to 'w' so that those people can modify the contents of these files as well. The final three characters show the permissions allowed to anyone who has a UserID on this Linux system. We prefer to refer to this set as "world". Our three primate files are "world-readable", that is, anyone in our Linux world can read their contents, but they cannot modify the contents of the files. This is the way we want to leave it. Click the right arrow to continue.