This book is designed for the course on OS, Unix and Shell Programming offered to students taking the DOEACCs A level certificate examination. The book will also be useful to the Diploma students who take a paper on the Unix operating system.Table of Contents: PART I OPERATING SYSTEM Chapter 1 Overview of Operating Systems Chapter 2 Process Management Chapter 3 Memory and File Management PART II UNIX & SHELL PROGRAMMING Chapter 4 Unix Basics Chapter 5 The Unix File System Chapter 6 The VI Editor Chapter 7 Shell as an Interpreter Chapter 8 Filters Chapter 9 Process Management In Unix Chapter 10 Shell Programming Chapter 11 C Programming Tools PART III UNIX INTERNALS AND NETWORKING Chapter 12 Unix Internals Chapter 13 System Calls Chapter 14 Administering File System Chapter 15 General System Administration Chapter 16 Networking Tools Chapter 17 The X Window System PART IV APPENDICCES Appendix A UNIX System Calls (System V) Appendix B Sample Question Paper Index