Korn-Shell-Programmierung Und Zeichenkettenverarbeitung Unter Unix/Linux
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Shell Scripting with Bash
Introduction to Shell Scripting with Bash Charles Jahnke Research Computing Services Information Services & Technology Topics for Today ● Introductions ● Basic Terminology ● How to get help ● Command-line vs. Scripting ● Variables ● Handling Arguments ● Standard I/O, Pipes, and Redirection ● Control Structures (loops and If statements) ● SCC Job Submission Example Research Computing Services Research Computing Services (RCS) A group within Information Services & Technology at Boston University provides computing, storage, and visualization resources and services to support research that has specialized or highly intensive computation, storage, bandwidth, or graphics requirements. Three Primary Services: ● Research Computation ● Research Visualization ● Research Consulting and Training Breadth of Research on the Shared Computing Cluster (SCC) Me ● Research Facilitator and Administrator ● Background in biomedical engineering, bioinformatics, and IT systems ● Offices on both CRC and BUMC ○ Most of our staff on the Charles River Campus, some dedicated to BUMC ● Contact: [email protected] You ● Who has experience programming? ● Using Linux? ● Using the Shared Computing Cluster (SCC)? Basic Terminology The Command-line The line on which commands are typed and passed to the shell. Username Hostname Current Directory [username@scc1 ~]$ Prompt Command Line (input) The Shell ● The interface between the user and the operating system ● Program that interprets and executes input ● Provides: ○ Built-in commands ○ Programming control structures ○ Environment -
Bash Crash Course + Bc + Sed + Awk∗
Bash Crash course + bc + sed + awk∗ Andrey Lukyanenko, CSE, Aalto University Fall, 2011 There are many Unix shell programs: bash, sh, csh, tcsh, ksh, etc. The comparison of those can be found on-line 1. We will primary focus on the capabilities of bash v.4 shell2. 1. Each bash script can be considered as a text file which starts with #!/bin/bash. It informs the editor or interpretor which tries to open the file, what to do with the file and how should it be treated. The special character set in the beginning #! is a magic number; check man magic and /usr/share/file/magic on existing magic numbers if interested. 2. Each script (assume you created “scriptname.sh file) can be invoked by command <dir>/scriptname.sh in console, where <dir> is absolute or relative path to the script directory, e.g., ./scriptname.sh for current directory. If it has #! as the first line it will be invoked by this command, otherwise it can be called by command bash <dir>/scriptname.sh. Notice: to call script as ./scriptname.sh it has to be executable, i.e., call command chmod 555 scriptname.sh before- hand. 3. Variable in bash can be treated as integers or strings, depending on their value. There are set of operations and rules available for them. For example: #!/bin/bash var1=123 # Assigns value 123 to var1 echo var1 # Prints ’var1’ to output echo $var1 # Prints ’123’ to output var2 =321 # Error (var2: command not found) var2= 321 # Error (321: command not found) var2=321 # Correct var3=$var2 # Assigns value 321 from var2 to var3 echo $var3 # Prints ’321’ to output -
Shell Script Getopts Example
Shell Script Getopts Example Gail is constrainedly cryoscopic after delegable Hilbert sag his parcloses illuminatingly. Gonzales often tootle irresistibly when tripersonal Giordano discomposed dissonantly and buffer her Barbarossa. Robert misdraws rompishly. Find that getopts script example we use later will contain whitespace separation with command Instantly share code, notes, and snippets. OPTARG is set to the period character found. They cease in many cases unneeded and brief fact that cartoon always press them its just like matter of personal coding style. File or directory or found. Operator precedence is used when there within five is more arguments. Typically, shell scripts use getopts to parse arguments passed to them. There did many ways to against your remedy environment. Nothing gets printed when no command line options are provided. The return status is zero unless an outcome is encountered while determining the name avid the he directory within an invalid option is supplied. The exit code will be success failure. Log in charge use details from one require these accounts. How does log lumber and cpu usage by an application? Now consider running it bore an unsupported option. No need only pass the positional parameters through to borrow external program. How can I check took a directory exists in a candy shell script? What extent its purpose? When optional, the fashion can buckle on led off additional functionality, as ugly a boolean option. In those cases, it contains a pointer to that parameter. How environment check ride a variable is set to Bash? Connect and deploy knowledge write a single location that is structured and fatigue to search. -
Research Computing and Cyberinfrastructure Team
Research Computing and CyberInfrastructure team ! Working with the Linux Shell on the CWRU HPC 31 January 2019 7 February 2019 ! Presenter Emily Dragowsky KSL Data Center RCCI Team: Roger Bielefeld, Mike Warfe, Hadrian Djohari! Brian Christian, Emily Dragowsky, Jeremy Fondran, Cal Frye,! Sanjaya Gajurel, Matt Garvey, Theresa Griegger, Cindy Martin, ! Sean Maxwell, Jeno Mozes, Nasir Yilmaz, Lee Zickel Preface: Prepare your environment • User account ! # .bashrc ## cli essentials ! if [ -t 1 ] then bind '"\e[A": history-search-backward' bind '"\e[B": history-search-forward' bind '"\eOA": history-search-backward' bind '"\eOB": history-search-forward' fi ! This is too useful to pass up! Working with Linux • Preamble • Intro Session Linux Review: Finding our way • Files & Directories: Sample work flow • Shell Commands • Pipes & Redirection • Scripting Foundations • Shell & environment variables • Control Structures • Regular expressions & text manipulation • Recap & Look Ahead Rider Cluster Components ! rider.case.edu ondemand.case.edu University Firewall ! Admin Head Nodes SLURM Science Nodes Master DMZ Resource ! Data Manager Transfer Disk Storage Nodes Batch nodes GPU nodes SMP nodes Running a job: where is it? slide from Hadrian Djohari Storing Data on the HPC table from Nasir Yilmaz How data moves across campus • Buildings on campus are each assigned to a zone. Data connections go from every building to the distribution switch at the center of the zone and from there to the data centers at Kelvin Smith Library and Crawford Hall. slide -
1 Introduction to Shell Programming
1 Introduction to Shell Programming This lecture is prepared for beginners who wish to learn the basics of shell scripting/programming plus introduction to power tools such as awk, sed, etc. 1.1 What is Linux Shell? • In Operating System, there is special program called Shell. Shell ac- cepts your instruction or commands in English (mostly) and if its a valid command, it is passed to kernel. • Shell is a user program or it's a environment provided for user interac- tion. • Shell is an command language interpreter that executes commands read from the standard input device (keyboard) or from a file. • Shell is not part of system kernel, but uses the system kernel to execute programs, create files etc. • To find all available shells in your system type following command: $ cat /etc/shells • Note that each shell does the same job, but each understand a different command syntax and provides different built-in functions. • In MS-DOS, Shell name is COMMAND.COM which is also used for same purpose, but it's not as powerful as our Linux Shells are! • To find your current shell type following command $ echo $SHELL • To use shell (You start to use your shell as soon as you log into your system) you have to simply type commands. 1 1.2 What is Shell Script ? • Normally shells are interactive. It means shell accept command from you (via keyboard) and execute them. • But if you use command one by one (sequence of 'n' number of com- mands) , the you can store this sequence of command to text file and tell the shell to execute this text file instead of entering the commands. -
Learning the Bash Shell, 3Rd Edition
1 Learning the bash Shell, 3rd Edition Table of Contents 2 Preface bash Versions Summary of bash Features Intended Audience Code Examples Chapter Summary Conventions Used in This Handbook We'd Like to Hear from You Using Code Examples Safari Enabled Acknowledgments for the First Edition Acknowledgments for the Second Edition Acknowledgments for the Third Edition 1. bash Basics 3 1.1. What Is a Shell? 1.2. Scope of This Book 1.3. History of UNIX Shells 1.3.1. The Bourne Again Shell 1.3.2. Features of bash 1.4. Getting bash 1.5. Interactive Shell Use 1.5.1. Commands, Arguments, and Options 1.6. Files 1.6.1. Directories 1.6.2. Filenames, Wildcards, and Pathname Expansion 1.6.3. Brace Expansion 1.7. Input and Output 1.7.1. Standard I/O 1.7.2. I/O Redirection 1.7.3. Pipelines 1.8. Background Jobs 1.8.1. Background I/O 1.8.2. Background Jobs and Priorities 1.9. Special Characters and Quoting 1.9.1. Quoting 1.9.2. Backslash-Escaping 1.9.3. Quoting Quotation Marks 1.9.4. Continuing Lines 1.9.5. Control Keys 4 1.10. Help 2. Command-Line Editing 2.1. Enabling Command-Line Editing 2.2. The History List 2.3. emacs Editing Mode 2.3.1. Basic Commands 2.3.2. Word Commands 2.3.3. Line Commands 2.3.4. Moving Around in the History List 2.3.5. Textual Completion 2.3.6. Miscellaneous Commands 2.4. vi Editing Mode 2.4.1. -
Shell Programming in Unix, Linux and OS X: the Fourth Edition of Unix
ptg18186768 ptg18186768 An iconic symbol of the American West, Monument Valley is one of the natural wonders of the world. The red-sand desert region is located within the range of the Navajo Nation on the Arizona-Utah border and is host to towering sandstone rock formations that have been sculpted over time and soar 400 to 1,000 feet above the valley floor. Three of the valley’s most photographed peaks are the distinctive East and West Mitten Buttes and Merrick Butte. Developer’s Library ESSENTIAL REFERENCES FOR PROGRAMMING PROFESSIONALS Developer’s Library books are designed to provide practicing programmers with unique, high-quality references and tutorials on the programming languages and technologies they use in their daily work. All books in the Developer’s Library are written by expert technology practitioners who are especially skilled at organizing and presenting information in a way that’s useful for other programmers. Key titles include some of the best, most widely acclaimed books within their topic areas: PHP & MySQL Web Development Python Essential Reference Luke Welling & Laura Thomson David Beazley ISBN-13: 978-0-321-83389-1 ISBN-13: 978-0-672-32862-6 MySQL Programming in Objective-C ptg18186768 Paul DuBois Stephen G. Kochan ISBN-13: 978-0-672-32938-8 ISBN-13: 978-0-321-56615-7 Linux Kernel Development Programming in C Robert Love Stephen G. Kochan ISBN-13: 978-0-672-32946-3 ISBN-13: 978-0-321-77641-9 Developer’s Library books are available at most retail and online bookstores, as well as by subscription from Safari Books Online at safari.informit.com Developer’s Library informit.com/devlibrary Shell Programming in Unix, Linux and OS X ptg18186768 Fourth Edition Stephen G. -
Command-Line Arguments Processing in Bash
Command-line arguments processing in bash Matěj Týč, OpenAlt 2017 1 / 24 Outline ● How people tend to design interface of their bash scripts? ● What exactly is command-line interface? ● How is bash diferent from other languages? ● What is the bash way? ● What really is the bash way. 2 / 24 Bash scripts Postgres backup script from postgres wiki 3 / 24 Bash scripts The bash docker (bocker) – example of a good script (as Awesome Bash says). 4 / 24 Bash scripts Ways how to pass data to your script: ● Env variables: LS_LONG=true ls ● “Confgg fles: ls ls_config_long.cfg ● Command-line arguments: ls --long 5 / 24 Command-line interface Let’s write an ls help script ls-help. In bash! ● # default argument $ ls-help > List all files in directory . ● # Multiple arguments, # the default is replaced $ ls-help foo bar > List all files in directories ‘foo’, ‘bar’ 6 / 24 Command-line interface Let’s write an ls help script ls-help. In bash! ● # Short boolean option $ ls-help -A foo bar > List all files in directories ‘foo’, ‘bar’ > Do not list implicit ‘.’ and ‘..’ ● # Long boolean option, reversed order # does the same $ ls-help foo bar --almost-all > List all files in directories ‘foo’, ‘bar’ > Do not list implicit ‘.’ and ‘..’ 7 / 24 Command-line interface Let’s write an ls help script ls-help. In bash! ● # Long option that takes value $ ls-help --width 10 > List all files in directory ‘.’ > Pad the width to 10 terminal columns ● # Separated by = is the same $ ls-help --width=10 > List all files in directory ‘.’ > Pad the width to 10 terminal columns 8 / 24 Command-line interface Let’s write an ls help script ls-help. -
La Kornshell: Lenguaje De Programación Y Comando
La KornShell: Lenguaje de Programación y Comando Una guía para programadores de Shell Scripts de Unix Jesús Alberto Vidal Cortés http://inicia.es/de/chube [email protected] www.kornshell.com Madrid, Agosto de 2001 Índice PARTE I: INTRODUCCIÓN......................................................................................................... 11 1. SOBRE EL LENGUAJE KORNSHELL ........................................................................................... 12 ¿Qué es una Shell?.............................................................................................................. 12 Beneficios del uso de ksh..................................................................................................... 13 Mejoras como Lenguaje de Comandos ................................................................................................................ 13 Mejoras como Lenguaje de Programación........................................................................................................... 14 Versiones a las que se aplica este manual............................................................................. 15 ¿Cómo obtener ksh?............................................................................................................ 16 2. NOTACIÓN UTILIZADA EN ESTE MANUAL..................................................................................... 18 General ............................................................................................................................... 18 Teclas sobre -
Squeezing Water from Stone: Kornshell in 2019
Squeezing Water from Stone: KornShell in 2019 Siteshwar Vashisht @SiteshwarV main() { printf(&unix["\021%six\012\0"],(unix)["have"]+"fun"-0x60);} ● Winner of IOCCC (The International Obfuscated C Code Contest) one line entry in 1987. ● Termed as best one liner ever received. ● Written by David Korn. What this talk is about ? ● It’s about AT&T KornShell (ksh, not mksh or pdksh). ● Brief status update from new upstream maintainers (Kurtis Rader and Siteshwar Vashisht). ● No deep dive in the source code. ● It is slightly extended version of my talk from FOSDEM 2019 and All Systems Go! 2019. /whois situ ● Siteshwar Vashisht. ● Based in Brno, Czech Republic. ● Maintainer of bash and ksh at Red Hat. ● Previously involved with fish shell and Sailfish OS. ● Current upstream maintainer of ksh. What is KornShell ? ● Direct descendant of Bourne shell. ● Initial development based on original bourne shell. ● Roots back to late 70’s and early 80’s. Spot the bug! #!/bin/bash echo $'hello world' | while read foo do bar="$foo" done echo "bar: " "$bar" $bar is not available outside loop. Bash forks last command in a new process and $bar is lost. Advantages ● Superior language specification (Support for Discipline functions, namespaces, compound data type, enums etc.). ● Better POSIX compliance. ● Fastest POSIX shell. Show me the numbers! $ cat test.sh for ((i=0;i<10000;i++)) do foo=$(echo "bar baz") done $ time bash test.sh $ time zsh test.sh $ time ksh test.sh real 0m2.977s real 0m2.433s real 0m0.078s user 0m2.032s user 0m1.570s user 0m0.062s sys 0m1.167s sys 0m1.233s sys 0m0.015s A 20 year old bug State of ksh in 2017 ● Previous developers have left. -
Answers to Selected Problems
Answers to selected problems Chapter 4 1 Whenever you need to find out information about a command, you should use man. With option -k followed by a keyword, man will display commands related to that keyword. In this case, a suitable keyword would be login, and the dialogue would look like: $ man -k login ... logname (1) - print user’s login name ... The correct answer is therefore logname.Tryit: $ logname chris 3 As in problem 4.1, you should use man to find out more information on date. In this case, however, you need specific information on date, so the command you use is $ man date The manual page for date is likely to be big, but this is not a problem. Remember that the manual page is divided into sections. First of all, notice that under section SYNOPSIS the possible format for arguments to date is given: NOTE SYNOPSIS date [-u] [+format] The POSIX standard specifies only two This indicates that date may have up to two arguments, both of arguments to date – which are optional (to show this, they are enclosed in square some systems may in brackets). The second one is preceded by a + symbol, and if you addition allow others read further down, in the DESCRIPTION section it describes what format can contain. This is a string (so enclose it in quotes) which 278 Answers to selected problems includes field descriptors to specify exactly what the output of date should look like. The field descriptors which are relevant are: %r (12-hour clock time), %A (weekday name), %d (day of week), %B (month name) and %Y (year). -
LINUX Commands
LINUX Commands alias Create an alias apropos Search Help manual pages (man -k) awk Find and Replace text, database sort/validate/index break Exit from a loop builtin Run a shell builtin bzip2 Compress or decompress named file(s) cal Display a calendar case Conditionally perform a command cat Display the contents of a file cd Change Directory cfdisk Partition table manipulator for Linux chgrp Change group ownership chmod Change access permissions chown Change file owner and group chroot Run a command with a different root directory cksum Print CRC checksum and byte counts clear Clear terminal screen cmp Compare two files comm Compare two sorted files line by line command Run a command - ignoring shell functions continue Resume the next iteration of a loop cp Copy one or more files to another location cron Daemon to execute scheduled commands crontab Schedule a command to run at a later time csplit Split a file into context-determined pieces cut Divide a file into several parts date Display or change the date & time dc Desk Calculator dd Data Dump - Convert and copy a file ddrescue Data recovery tool declare Declare variables and give them attributes df Display free disk space diff Display the differences between two files diff3 Show differences among three files dig DNS lookup dir Briefly list directory contents dircolors Colour setup for `ls' dirname Convert a full pathname to just a path dirs Display list of remembered directories du Estimate file space usage echo Display message on screen egrep Search file(s) for lines that match an