This book presents a detailed discussion on basics of Operating system, Linux commands, utilities and Shell programming in easy-to-understand language.and Concepts of process management and Investigation, Linux file system, System configuration tools, Shell features, Standard input /output, piping and wildcards, vim-advance text editor, X-Window system and text processing tools are discussed in such a manner that students of all streams namely arts, commerce and science can easily understand such complex subjects without any difficulty.and Bash shell and its configuration, file processing and advance topics in user groups and permission are portrayed in a very comprehensive manner to build a strong foundation.and Shell programming is explained with maximum number of examples.