pyttymon - - A simple daemon that monitors and limits usage of ttys. It is implemented in Python. A simple config file can specify monthly, daily, session, and idle limits based on tty, user, group, and ttys in use.
Unix and Linux Commands - - Basic as well as more obscure commands for Unix/Linux operating systems.
Unix Filesystem - - Description of how the filesystem works internally.
Unix Manuals - - Brief Unix tutorial, online man pages and reference materials for the Unix operating system and common Unix utilities.
Unix Signals and Process Groups - - Short survey of Unix signal handling and process groups, conceptually and with interface descriptions. Compares System V Release 3, System V Release 4, BSD, and POSIX variants.