RHCSA Rapid Track

Files have three categories to which permissions apply. A file is owned by a user, a single group, and other users. The most specific permission applies. User permissions override group permissions and group permissions override other permissions.

The ls command with the -l option expands the file listing to include both the file permissions and ownership.

The chmod command changes file permissions from the command line. There are two methods to represent permissions, symbolic (letters) and numeric (digits).

The chown command changes file ownership. The -R option recursively changes the ownership of a directory tree.

The umask command without arguments displays the current umask value of the shell. Every process on the system has a umask. The default umask values for Bash are defined in the /etc/profile and /etc/bashrc files.