Linux

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