Manipulating file permissions and ownership

After reading the first part of this chapter, you should have a decent understanding of Linux file permissions, and how read, write, and executed are used on a user, group, and other levels to ensure that files are exposed exactly as required. However, up until this point, we've been dealing with static permissions. When administering a Linux system, you will most likely spend a fair bit of time adjusting and troubleshooting permissions. In this part of the book, we'll be exploring the commands we can use to manipulate the permissions on files.

chmod, umask

Let's circle back to our testfile. It has the following permissions: -rw-rw----. Read/writable by user and group, readable by others. While these permissions might be fine for most files, they are definitely not a great fit for all files. What about private files? You would not want those to be readable by everyone, perhaps not even by group members.

The Linux command to change permissions on a...