$PATH A variable that contains a list of directories that are searched for executable files when a user enters a command.
. The current directory. Its value can be requested using the pwd command.
absolute filename A filename that is complete and starts with the name of the root directory, including all directories up to the current file or directory.
access control list (ACL) In Linux permissions, a system that makes it possible to grant permissions to more than one user and more than one group. Access control lists also allow administrators to set default permissions for specific directories.
anacron A service that ensures that vital cron jobs can be executed when the server is down at the moment that the job normally should be ...