Hackers Toolkit v2.0

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UNIX for Intermediate Users Developed by: User Liaison Section, D-7131 [Name and numbers removed at author's request] Revision Date: TABLE OF CONTENTS I. INTRODUCTION........................................................................ ii A. Audience..................................................................... ii B. Course Objectives............................................................ ii C. Course Handout Conventions...................................................iii 1. THE FILE CALLED .profile AND PROCESSES.............................................. 1 1.1 HOME........................................................................ 1 1.2 PATH........................................................................ 2 1.3 INGRES Environment Variables................................................ 2 1.4 ING_HOME.................................................................... 3 1.5 TERM_INGRES................................................................. 3 1.6 ING_EDIT.................................................................... 3 1.7 Processes................................................................... 4 1.8 Executing a Command......................................................... 4 1.9 Process Identification...................................................... 5 1.10 Interrupt Handling......................................................... 7 2. COMPILING "C" PROGRAMS............................................................... 10 2.1 "C": Sample Program with a Main and Two Functions in One ............................................................ 10 2.2 "C": Compiling a Program.................................................... 12 2.3 "C": Renaming the Executable Module......................................... 13 2.4 "C": Giving a Name to the Output File....................................... 14 2.5 "C": Producing an Assembly Listing.......................................... 15 2.6 "C": Main and Two Functions in Three Separate Source Files.............................................................. 16 2.7 "C": Compiling but Not Producing an Executable Module.................................................................... 17 3. COMPILING FORTRAN PROGRAMS......................................................... 18 3.1 FORTRAN: Sample Program a Main and Two Subroutines............................................................... 18 3.2 FORTRAN: Compiling a Program................................................ 19 3.3 FORTRAN: Renaming the Executable Module..................................... 20 3.4 FORTRAN: Giving a Name to the Output File................................... 21 3.5 FORTRAN: Producing an Assembly Listing...................................... 22 3.6 FORTRAN: Main and Two Subroutines in Three Separate Source Files........................................ 23 3.7 FORTRAN: Compiling But Not Producing an Executable Module.................................................................... 24 3.8 FORTRAN: Compiling Object Files to Produce an Executable Module....................................... 25 4. COMPILING COBOL PROGRAMS............................................................ 26 4.1 COBOL: Sample Program with a Main and Two Subroutines............................................................... 26 4.2 COBOL: Compiling a Program.................................................. 27 4.3 COBOL: Running a Program.................................................... 28 Workshop 2-4..................................................................... 30 5. UNIX TOOLS.......................................................................... 34 5.1 The make Utility............................................................ 34 p: A Pattern Matching Filter............................................................ 37 5.2.1 More on Regular Expressions........................................ 38 5.2.2 Closure............................................................ 42 5.2.3 Some Nice grep Options ................................ 43 5.2.4 Summary of Regular Expression Characters........................... 44 5.3 sed: Edit a File to Standard Output......................................... 45 5.4 awk: A Pattern Matching Programming Language................................ 49 5.5 sort: Sort a File........................................................... 53 5.6 Archiver and Library Maintainer............................................. 56 5.7 Creating an Archive File with Object Modules................................ 57 5.8 Verifying the Contents of the Archive File.................................. 57 5.9 Removing Duplicate Object Files............................................. 58 5.10 Compiling Main and Archive Files........................................... 58 Workshop 5....................................................................... 59 6. UNIX UTILITIES PART I - DISPLAY AND MANIPULATE FILES................................ 63 7. UNIX UTILITIES PART II - DISPLAY AND ALTER STAUTS................................... 73 8. UNIX UTILITIES PART III - MISCELLANEOUS............................................. 85 9. ADVANCED FEATURES OF FTP............................................................ 90 9.1 Initializing FTP on UMAX.................................................... 91 9.2 Multiple File Transfers..................................................... 92 9.3 Auto Login Feature.......................................................... 93 9.4 Macros...................................................................... 95 9.5 Filename Translation........................................................ 96 9.6 Aborting Transfers.......................................................... 97 9.7 More Remote Computer Commands............................................... 98 Workshop 10...................................................................... 99 APPENDIX A - sh.........................................................................101 APPENDIX B - ftp........................................................................116 APPENDIX C - C Compiler.................................................................128 APPENDIX D - FORTRAN Compiler...........................................................137 APPENDIX E - lint.......................................................................147 APPENDIX F - cb.........................................................................151 APPENDIX G - ar.........................................................................152 INDEX...................................................................................157 I. INTRODUCTION A. Audience This course is for individuals who need to use utilities and advanced features of the UNIX operating system. B. Course Objectives Upon successful completion of this course the student will be able to: 1. Compile C, FORTRAN, and COBOL programs. 2. Create processes to run in the background 3. Use advanced features of FTP such as: multiple file transfers, auto logins, macros, globbing, filename translation, aborting transfers, and other remote computer commands. 4. Use UNIX utility programs such as grep, sed, awk, sort, and others. 5. Use the make utility. 6. Understand processes, including structure, executing a command, process identification, exit status, plus . (dot) and exec processing. C. Course Handout Conventions There are several conventions used in this handout for consistency and 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. ┌───────────────────────────────────────────────────────────────┐ │ │ │ Multimax, Nanobus, and UMAX are trademarks of │ │ Encore Computer Corporation. │ │ │ │ │ │ Annex is a trademark of XYLOGICS, Inc. │ │ │ │ │ │ UNIX and Teletype are registered trademarks of │ │ AT&T Bell Laboratories │ │ │ │ │ │ Ethernet is a trademark of Xerox Corporation │ │ │ └───────────────────────────────────────────────────────────────┘ 1. UNIX PROCESSES AND A FILE CALLED .profile 1.1 Processes A process is the execution of a command by UNIX. Processes can also be executed by the operating system itself. Like the file structure, the process structure is hierarchical. It contains parents, children, and even a root. A parent can fork (or spawn) a child process. That child can, in turn, fork other processes. The first thing the operating system does to begin execution is to create a single process, PID number 1. PID stands for Process Identification. This process will hold the same position as the root directory in the file structure. This process is the ancestor to all processes that each user works with. It forks a process for each terminal. Each one of these processes becomes a Shell process when the user logs in. 1.2 Process Identification The UNIX operating system assigns a unique process identification number (PID) to each process. It will keep the same PID as long as the process is in existence. During one session, the same process is always executing the login Shell. When you execute another command, a new process is forked and a new PID is assigned to that process. When that child process is finished, you are returned to the login process, which is running the Shell, and that parent process has the same PID as when you logged in. The Shell stores the PID in Shell variable called $$. The PID can also be shown with the process status (ps) command. The format for ps is as follows: ╔═══════════════════════════════════════════════════════════════╗ ║ Command Format: ps [options] ║ ║ ║ ║ See on-line manual for options ║ ╚═══════════════════════════════════════════════════════════════╝ With no options given the ps command will give you certain information about processes associated with the controlling terminal. The output consists of a short listing containing the process id, terminal id, cumulative execution time, and the command name. Otherwise, options will control the display. Sample session: ┌────────────────────────────────────────────────────────────────────────────┐ │ $echo $$ │ │ 8347 │ │ $ps │ │ PID TTY TIME COMMAND │ │ 8347 rt021a0 0:03 ksh │ │ 8376 rt021a0 0:06 ps │ │ $ │ └────────────────────────────────────────────────────────────────────────────┘ The PID numbers of the Shell are the same in the sample session because the Shell will substitute its own PID number for $$. The Shell makes the substitution before it forks a new process to execute the echo command. Therefore, echo will display the PID number of the process that called it, not the PID of the process that is executing it. The -l option will display more information about the processes. Sample Session: ┌──────────────────────────────────────────────────────────────────────────────────────────┐ │ $ps -l │ │ F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME COMD │ │ f0000 S 115 8347 309 2 30 20 1009000 140 94014 rt021a0 0:03 ksh │ │ f0000 O 115 8386 8347 16 68 20 1308000 72 rt021a0 0:01 ps │ │ $ps -l │ │ F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME COMD │ │ f0000 S 115 8347 309 1 30 20 1009000 140 94014 rt021a0 0:03 ksh │ │ f0000 O 115 8387 8347 26 73 20 1146000 72 rt021a0 0:01 ps │ │ $ │ └──────────────────────────────────────────────────────────────────────────────────────────┘ 1.3 Executing a Command When you give a command to the Shell, it will fork a process to execute the command. While the child process is executing the command, the parent will go to sleep. Sleeping means that the process will not use any CPU time. It remains inactive until it is awakened. When the child process has finished executing the command, it dies. The parent process, which is running the Shell, wakes up and prompts you for another command. When you request a process to run in the background (by ending the command line with an ampersand character (&), the Shell forks a child process that is allowed to run to completion. The parent process will report the PID of the child process and then prompt you for another command. The child and parent are now independent processes. 1.4 The . (dot) and exec Commands There are two ways to execute a program without forking a new process. The . (dot) command will execute the script as part of the current process. When the new script has finished executing, the current process will continue to execute the original script. The exec command will execute the new script in place of (overlays) the original script and never returns to the original script. The . (dot) command will not execute compiled files (binary) and it does not require execute permission on the script file that is being executed. The exec command does require access permission to either a binary program or a shell script. Sample session: ┌───────────────────────────────────────────────────────────────┐ │ $ls -l prog2 │ │ -rw-r--r-- 1 teacher class 22 Jan 18 10:30 prog2 │ │ $cat prog2 │ │ echo 'prog2 PID =' $$ │ │ $cat dot_example │ │ echo $0 'PID=' $$ │ │ . prog2 │ │ echo 'This line is executed' │ │ $dot_example │ │ dot_example PID= 6942 │ │ prog2 PID = 6942 │ │ This line is executed │ │ $ │ └───────────────────────────────────────────────────────────────┘ The exec command will overlay the sh and control will never return to the calling script. Let's look at another example with a call to prog2 using exec instead of . (dot): Sample session: ┌───────────────────────────────────────────────────────────────┐ │ $ls -l prog2 │ │ -rwxr-xr-x 1 teacher class 22 Jan 18 10:30 prog2 │ │ $cat prog2 │ │ echo 'prog2 PID =' $$ │ │ $cat exec_example │ │ echo $0 'PID=' $$ │ │ exec prog2 │ │ echo 'This line is never executed' │ │ $exec_example │ │ exec_example PID= 6950 │ │ prog2 PID = 6950 │ │ $ │ │ │ └───────────────────────────────────────────────────────────────┘ Background Processing When a program is running in background you do not have to wait for it to finish before starting another program. This is useful because you can start long/large jobs and then continue to do another task on your terminal. To run a program in background simply type an ampersand character (&) at the end of the command line before the (Ret) key. The Shell will return the PID of the background process and then give you another system prompt. Sample session: ┌───────────────────────────────────────────────────────────────┐ │ $ls -l | lp & │ │ [1] 21334 │ │ $request id is mt_600-2736 (standard input) │ │ │ │ $ │ └───────────────────────────────────────────────────────────────┘ If the background task sends output to standard output and you fail to redirect it, the output will appear on your terminal even if you are running another program at the time. It is necessary to use the kill command to stop a process that is running in background the (DEL) key or its equivalent will not work. Exit Status When a process stops executing for any reason, it will return an exit status to the parent process. This exit status is also referred to as a condition code or return code.The Shell stores the exit status in a Shell variable called $?. By convention, a non-zero exit status means that it has a false value and the command failed. On the other hand, a zero status indicates true and the command was successful. It is possible for you to specify the exit status when you exit a script. This is done by specifying the number to be used as the exit status using the exit command. The following script is an example: Sample Session: ┌───────────────────────────────────────────────────────────────┐ │ $cat exit_example │ │ echo 'This program returns an exit status' │ │ echo 'of 7.' │ │ exit 7 │ │ $exit_example │ │ This program returns an exit status │ │ of 7. │ │ $echo $? │ │ 7 │ │ $echo $? │ │ 0 │ │ $ │ │ │ └───────────────────────────────────────────────────────────────┘ This script will display the message and then exit with an exit code of 7. The exit status is stored in the Shell variable called $?. The second echo command above displays the exit status of the first echo command. Since it completed successfully it has a value of zero. 1.4 Interrupt Handling A signal is a report to a process about a condition. UNIX uses these signals to report bad system calls, broken pipes, illegal instructions, and other conditions. There are three signals that are useful when programming in the Shell. They are the terminal interrupt signal (number 2), the kill signal (number 9) and the software termination signal (number 15). You can use the trap command to capture a signal and then take whatever action you specify. It can close files or finish other processing that needs to be done, display a message, terminate execution immediately, or ignore the signal. ╔═══════════════════════════════════════════════════════════════╗ ║ Command Format: trap ['commands'] signal_numbers ║ ║ ║ ║ See online man pages for details ║ ║ ║ ╚═══════════════════════════════════════════════════════════════╝ The signal_numbers are the numbers corresponding to the signals that will be trapped by the trap command. There must be at least one number present. The 'commands' portion of the command is optional. If it is not present, the command resets the trap to its initial condition, which is to exit the program. When the commands is present the Shell executes the commands when it catches one of the signals. After executing the commands, the Shell continues executing the script where it left off. You can interrupt a program you are running in the foreground by pressing the Delete key. When you press this key a signal (number 2), a terminal interrupt, to the program. The Shell will terminate the execution of the program if the program does not trap the signal. The following example demonstrates the trap command that will trap the signal and return an exit status of 1. Sample session: ┌───────────────────────────────────────────────────────────────┐ │ $cat inter │ │ trap 'echo PROGRAM INTERRUPTED; exit 1' 2 │ │ while (true) │ │ do