UNIX Bourne Shell Programming                    Developed by:                         User Liaison Section, D-7131                         Denver Office                       [Name and number removed at author's                     request]                    Revision Date:  February 7, 1991I.  INTRODUCTION..............................................  v     A.  Audience.............................................  v     B.  Course Objectives....................................  v     C.  Course Handout Conventions........................... vi1.  BOURNESHELL OVERVIEW......................................  1     1.1  What is the BourneShell?............................  2     1.2  Making a Bourne Shell Script Executable.............  3     1.3  Tracing Mechanisms..................................  6     Workshop 1...............................................  92.  USER, SHELL, AND READ-ONLY SHELL VARIABLES................ 11     2.1  User Variables...................................... 11     2.2  Shell Variables..................................... 14          2.2.1  HOME......................................... 14          2.2.2  IFS.......................................... 15          2.2.3  MAIL......................................... 15          2.2.4  MAILPATH..................................... 15          2.2.5  MAILCHECK.................................... 16          2.2.6  PATH......................................... 16          2.2.7  PS1.......................................... 17          2.2.8  PS2.......................................... 17     2.3  Read-Only User Variables............................ 18     2.4  Read-Only Shell Variables........................... 19          2.4.1  Name of the Calling Program.................. 19          2.4.2  Arguments.................................... 19          2.4.3  Shift........................................ 21          2.4.4  Set.......................................... 22          2.4.5  expr......................................... 23     Workshop 2............................................... 273.  POSITIONAL PARAMETERS..................................... 33     3.1  Reading Input Into a Shell Variable................. 34     3.2  Command Substitution................................ 36     3.3  Comments in BourneShell Scripts..................... 38     3.4  BourneShell Environment - Exporting Variables....... 39     Workshop 3............................................... 414.  CONTROL CONSTRUCTS:....................................... 45     4.1  Types of Tests Used with Control Constructs:........ 46     4.2  Test on Numeric Values.............................. 47     4.3  Test on Character Strings........................... 47     4.4  Test on File Types.................................. 49     4.5  if then............................................. 50     4.6  if then else........................................ 52     4.7  if then elif........................................ 54     4.8  for................................................. 55     4.9  while............................................... 57     4.10  until.............................................. 58     4.11  case............................................... 60     Workshop 4............................................... 635. COMPILING PROGRAMS IN UNIX................................. 67     5.1  "C": Sample Program with a Main and Two Functions               in One        ................................. 67     5.2  "C": Compiling a Program............................ 69     5.3  "C": Renaming the Executable Module................. 71     5.4  "C": Giving a Name to the Output File............... 72     5.5  "C": Producing an Assembly Listing.................. 73     5.6  "C": Main and Two Functions in Three Separate Source               Files.......................................... 74     5.7  "C": Compiling but Not Producing an Executable               Module............................................. 75     5.8  FORTRAN: Sample Program a Main and Two Subroutine... 76     5.9  FORTRAN: Compiling a Program........................ 77     5.10  FORTRAN: Renaming the Executable Module............ 79     5.11  FORTRAN: Giving a Name to the Output File.......... 80     5.12  FORTRAN: Producing an Assembly Listing............. 81     5.13  FORTRAN: Main and Two Subroutines in Three Separate                    Source Files.............................. 82     5.14  FORTRAN: Compiling But Not Producing an Executable                    Module.................................... 83     5.15  FORTRAN: Compiling Object Files to Produce an                    Executable Module............................. 84     5.16  COBOL: Sample Program with a Main and Two                          Subroutines................................. 85     5.17  COBOL: Compiling a Program......................... 86     5.18  COBOL: Running a Program........................... 87     Workshop 5............................................... 896.  UNIX TOOLS................................................ 95     6.1  Processes........................................... 95     6.2  Executing a Command................................. 95     6.3  Process Identification.............................. 95     6.4  grep: A Pattern Matching Filter..................... 98          6.4.1  More on Regular Expressions.................. 99          6.4.2  Closure......................................103          6.4.3  Some Nice grep Options ......................104          6.4.4  Summary of Regular Expression Characters.....105     6.5  sed: Edit a File to Standard Output.................106     6.6  awk: A Pattern Matching Programming Language........110     6.7  sort: Sort a File...................................114     6.8  What Other Useful UNIX Tools are Available..........117     6.9  Archiver and Library Maintainer.....................118          6.9.1  ar: Creating an Archive File with Object                     Modules.....................................119          6.9.2  ar: Verifying the Contents of the Archive                     File.......................................119          6.9.3  ar: Removing Duplicate Object Files..........120          6.9.4  ar: Compiling Main and Archive Files.........120     Workshop 6...............................................1217.  VAX DCL TO UNIX SHELL SCRIPT CONVERSION...................125     7.1  Processes...........................................127     7.2  Pipes...............................................128     7.3  Input, Output, and Error Redirection................129     7.4  Command Structure and File Naming Conventions.......131     7.5  File Management Commands............................133     7.6  Metacharacters......................................135     7.7  Wildcards: Are They Really Wild?....................136     7.8  Summary.............................................137     Workshop 7...............................................1398.  ADVANCED FEATURES OF FTP..................................143     8.1  Initializing FTP on UMAX............................144     8.2  Multiple File Transfers.............................145     8.3  Auto Login Feature..................................146     8.4  Macros..............................................148     8.5  Filename Translation................................149     8.6  Aborting Transfers..................................150     8.7  More Remote Computer Commands.......................151     Workshop 8...............................................1539.  OPTIONAL CHAPTER - KORNSHELL PROGRAMMING..................155     9.1  KornShell Variables.................................155     9.2  User Defined Variables..............................157     9.3  Values of Variables Between Child and Parent          Processes...........................................158     9.4  ksh: Aliases........................................159     9.5  ksh: Command Line Editing...........................161     9.6  ksh: Interactive Command Line Editing...............162     9.7  ksh: Functions......................................164     9.8  ksh: The Select Construct...........................166     9.9  ksh: Tracing and Conditional Execution..............168     Workshop 9...............................................169APPENDIX A - sh...............................................173APPENDIX B - test.............................................189APPENDIX C - expr.............................................193APPENDIX D - ftp..............................................195APPENDIX E - cc...............................................209APPENDIX F - f77..............................................219APPENDIX G - lint.............................................231APPENDIX H - cb...............................................235APPENDIX I - ar...............................................237APPENDIX J - time.............................................243APPENDIX K - ksh..............................................245INDEX.........................................................279I.  INTRODUCTIONA.  AudienceThis course is for individuals who have completed "UNIX forBeginning Users" (or equivalent experience) and want to write UNIXBourneShell script files.  A script file contains a sequence ofUNIX commands which can be executed by entering one command.  Itis assumed that the student already has a good understanding of theUNIX operating system, be able to use a UNIX editor, and befamiliar with a computer terminal or typewriter keyboard.B.  Course ObjectivesUpon successful completion of this course the student will be ableto:     1.   Write moderately complex BourneShell scripts.     2.   Make a BourneShell script executable.     3.   Demonstrate how to use the following BourneShell          commands: shift, exit, expr, test, if then, if then else,          if then elif, for, while, until, and case.     4.   Use the following BourneShell constructs: tracing          mechanisms (for debugging), user variables, BourneShell          variables, read-only variables, positional parameters,          reading input to a BourneShell script, command          substitution, comments, and exporting variables.  In          addition, test on numeric values, test on file type, and          test on character strings are covered.     6.   Create a ".profile" script to customize the user          environment.     7.   Use advanced features of File Transfer Protocol (FTP)     8.   Compile source code into object and executable modules.     9.   Optional: KornShell programming.  This is of primary          interest to programmers.     10.  Convert VMS DCL command files to UNIX Shell.C.  Course Handout ConventionsThere are several conventions used in this handout for consistencyand easier interpretation:     1.   Samples of actual terminal sessions are single-lined          boxed.     2.   User entries are shown in bold print and are underlined.          exit     3.   All keyboard functions in the text will be bold.            (Ret)               Backspace          Tab                 Ctrl-F6          Print (Shift-F7)    Go to DOS (1)          NOTE:     (Ret) indicates the Return or Enter key located                    above the right Shift key.     4.   Examples of user entries not showing the computer's          response are in dotted-lined boxes.                                   5.   Command formats are double-lined boxed.     6.   Three dots either in vertical or horizontal alignment          mean continuation or that data is missing from diagram.                                                                 赺______________________________________________________________