AN INTRODUCTION TO UNIX SYSTEMS ADMINISTRATION David Jones Front Cover Taken from an original slide by Kenny Paul ([email protected]) and used with his kind permission. Original text: LISA VII New Systems Administrators BOF November 1st, 1993, Monterey California Fig. 1: A Typical Systems Administrator. David Jones (11/30/94) Page 2. Table of Contents INTRODUCTION..............................................................................................9 Exercises and Review Questions.................................................................................................... 9 Format and Fonts .......................................................................................................................... 9 Reading the Guide....................................................................................................................... 10 Chapter Descriptions ................................................................................................................... 11 Acknowledgements...................................................................................................................... 14 Trademarks ................................................................................................................................. 14 Feedback ..................................................................................................................................... 14 FOUNDATIONS.............................................................................................15 Objectives.................................................................................................................................... 15 Introduction................................................................................................................................. 15 What Systems Administrators do................................................................................................. 16 What Systems Administrators need to know ................................................................................ 18 Why UNIX? ................................................................................................................................ 18 UNIX Past, Present and Future.................................................................................................... 19 Linux .......................................................................................................................................... 19 Some Necessary Knowledge ........................................................................................................ 20 Pre-emptive versus Non-preemptive............................................................................................. 21 The vi Editor ............................................................................................................................... 21 Conclusions................................................................................................................................. 26 Review Questions ........................................................................................................................ 27 BASIC UNIX...................................................................................................28 Objectives.................................................................................................................................... 28 Philosophy and Format of UNIX Commands ............................................................................... 28 A Command for Everything......................................................................................................... 29 The Basic Commands.................................................................................................................. 29 File Permissions .......................................................................................................................... 30 Symbolic and Absolute Modes..................................................................................................... 33 Changing File Permissions .......................................................................................................... 34 When is a Command not a Command?........................................................................................ 37 The Shell..................................................................................................................................... 38 Executing a Command ................................................................................................................ 39 Other Special Characters ............................................................................................................. 42 Quotes......................................................................................................................................... 42 Getting Help................................................................................................................................ 44 Conclusion .................................................................................................................................. 46 Review Questions ........................................................................................................................ 46 David Jones (11/30/94) Page 3 Table of Contents SHELL PROGRAMMING...............................................................................47 Objectives.................................................................................................................................... 47 Introduction................................................................................................................................. 47 The Basics of Shell Programming................................................................................................ 47 Shell Support for Programming................................................................................................... 49 Shell Comments .......................................................................................................................... 50 Using Shell Variables.................................................................................................................. 50 Predefined Shell Variables........................................................................................................... 52 The exit Command...................................................................................................................... 55 The Conditional Commands........................................................................................................ 56 The test Command ...................................................................................................................... 58 Repeated Action Commands........................................................................................................ 61 Some Other Useful Commands.................................................................................................... 63 Conclusion .................................................................................................................................. 64 Review Questions ........................................................................................................................ 65 ADVANCED UNIX USE .................................................................................66 Objectives.................................................................................................................................... 66 Introduction................................................................................................................................. 66 Shell Functions............................................................................................................................ 67 Input/Output for Shell Programs.................................................................................................. 68 Trapping Signals......................................................................................................................... 71 Regular Expressions .................................................................................................................... 75 ex, vi and Regular Expressions.................................................................................................... 78 awk ............................................................................................................................................. 81 Perl ............................................................................................................................................. 82 Conclusions................................................................................................................................. 83 Review Questions ........................................................................................................................ 84 SYSTEMS ADMINISTRATION THEORY ......................................................85 Objectives.................................................................................................................................... 85 Introduction................................................................................................................................. 85 Policy and Penalty ......................................................................................................................