Free operating system for various platforms that can be built and configured by the user or users to best suit their system needs. Chart includes detailed information on: * logging in& out * user& group manipulation * LINUX shells& command line * the file system * I/O redirection * wildcards& the VI editor * permissions& ownership * shell& user variables * FTP (File Transfer Protocol) * archiving files& directories * login shell scripts * job control& processes * command summary