The Linux Command Line

Total Page:16

File Type:pdf, Size:1020Kb

The Linux Command Line The Linux Command Line Second Internet Edition William E. Shotts, Jr. A LinuxCommand.org Book Copyright ©2008-2013, William E. Shotts, Jr. This work is licensed under the Creative Commons Attribution-Noncommercial-No De- rivative Works 3.0 United States License. To view a copy of this license, visit the link above or send a letter to Creative Commons, 171 Second Street, Suite 300, San Fran- cisco, California, 94105, USA. Linux® is the registered trademark of Linus Torvalds. All other trademarks belong to their respective owners. This book is part of the LinuxCommand.org project, a site for Linux education and advo- cacy devoted to helping users of legacy operating systems migrate into the future. You may contact the LinuxCommand.org project at http://linuxcommand.org. This book is also available in printed form, published by No Starch Press and may be purchased wherever fine books are sold. No Starch Press also offers this book in elec- tronic formats for most popular e-readers: http://nostarch.com/tlcl.htm Release History Version Date Description 13.07 July 6, 2013 Second Internet Edition. 09.12 December 14, 2009 First Internet Edition. 09.11 November 19, 2009 Fourth draft with almost all reviewer feedback incorporated and edited through chapter 37. 09.10 October 3, 2009 Third draft with revised table formatting, partial application of reviewers feedback and edited through chapter 18. 09.08 August 12, 2009 Second draft incorporating the first editing pass. 09.07 July 18, 2009 Completed first draft. Table of Contents Introduction....................................................................................................xvi Why Use The Command Line?.....................................................................................xvi What This Book Is About..............................................................................................xvii Who Should Read This Book.......................................................................................xvii What's In This Book.....................................................................................................xviii How To Read This Book..............................................................................................xviii Prerequisites............................................................................................................xix Why I Don't Call It “GNU/Linux”...........................................................................xix Acknowledgments..........................................................................................................xx Your Feedback Is Needed!............................................................................................xx What's New In The Second Internet Edition.................................................................xxi Further Reading............................................................................................................xxi Colophon.......................................................................................................................xxi Part 1 – Learning The Shell..............................................................1 1 – What Is The Shell?.....................................................................................2 Terminal Emulators..........................................................................................................2 Your First Keystrokes......................................................................................................2 Command History.......................................................................................................3 Cursor Movement.......................................................................................................3 A Few Words About Mice And Focus....................................................................3 Try Some Simple Commands..........................................................................................4 Ending A Terminal Session..............................................................................................5 The Console Behind The Curtain..........................................................................5 Summing Up....................................................................................................................5 Further Reading...............................................................................................................6 2 – Navigation...................................................................................................7 Understanding The File System Tree..............................................................................7 The Current Working Directory........................................................................................7 Listing The Contents Of A Directory................................................................................8 Changing The Current Working Directory.......................................................................9 Absolute Pathnames..................................................................................................9 Relative Pathnames...................................................................................................9 Some Helpful Shortcuts............................................................................................11 Important Facts About Filenames........................................................................11 i Summing Up..................................................................................................................12 3 – Exploring The System.............................................................................13 More Fun With ls...........................................................................................................13 Options And Arguments............................................................................................14 A Longer Look At Long Format.................................................................................16 Determining A File's Type With file................................................................................17 Viewing File Contents With less....................................................................................17 What Is “Text”?.....................................................................................................17 Less Is More........................................................................................................19 A Guided Tour................................................................................................................19 Symbolic Links...............................................................................................................23 Hard Links.....................................................................................................................24 Summing Up..................................................................................................................24 Further Reading.............................................................................................................24 4 – Manipulating Files And Directories........................................................25 Wildcards.......................................................................................................................25 Character Ranges................................................................................................27 Wildcards Work In The GUI Too..........................................................................27 mkdir – Create Directories.............................................................................................28 cp – Copy Files And Directories....................................................................................28 Useful Options And Examples..................................................................................29 mv – Move And Rename Files......................................................................................30 Useful Options And Examples..................................................................................30 rm – Remove Files And Directories...............................................................................31 Useful Options And Examples..................................................................................31 Be Careful With rm!.............................................................................................32 ln – Create Links............................................................................................................33 Hard Links................................................................................................................33 Symbolic Links..........................................................................................................33 Let's Build A Playground................................................................................................34 Creating Directories..................................................................................................34 Copying Files............................................................................................................34 Moving And Renaming Files.....................................................................................35 Creating Hard Links..................................................................................................37 Creating Symbolic Links...........................................................................................38
Recommended publications
  • Administering Unidata on UNIX Platforms
    C:\Program Files\Adobe\FrameMaker8\UniData 7.2\7.2rebranded\ADMINUNIX\ADMINUNIXTITLE.fm March 5, 2010 1:34 pm Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta UniData Administering UniData on UNIX Platforms UDT-720-ADMU-1 C:\Program Files\Adobe\FrameMaker8\UniData 7.2\7.2rebranded\ADMINUNIX\ADMINUNIXTITLE.fm March 5, 2010 1:34 pm Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Beta Notices Edition Publication date: July, 2008 Book number: UDT-720-ADMU-1 Product version: UniData 7.2 Copyright © Rocket Software, Inc. 1988-2010. All Rights Reserved. Trademarks The following trademarks appear in this publication: Trademark Trademark Owner Rocket Software™ Rocket Software, Inc. Dynamic Connect® Rocket Software, Inc. RedBack® Rocket Software, Inc. SystemBuilder™ Rocket Software, Inc. UniData® Rocket Software, Inc. UniVerse™ Rocket Software, Inc. U2™ Rocket Software, Inc. U2.NET™ Rocket Software, Inc. U2 Web Development Environment™ Rocket Software, Inc. wIntegrate® Rocket Software, Inc. Microsoft® .NET Microsoft Corporation Microsoft® Office Excel®, Outlook®, Word Microsoft Corporation Windows® Microsoft Corporation Windows® 7 Microsoft Corporation Windows Vista® Microsoft Corporation Java™ and all Java-based trademarks and logos Sun Microsystems, Inc. UNIX® X/Open Company Limited ii SB/XA Getting Started The above trademarks are property of the specified companies in the United States, other countries, or both. All other products or services mentioned in this document may be covered by the trademarks, service marks, or product names as designated by the companies who own or market them. License agreement This software and the associated documentation are proprietary and confidential to Rocket Software, Inc., are furnished under license, and may be used and copied only in accordance with the terms of such license and with the inclusion of the copyright notice.
    [Show full text]
  • Pcoip® Host Software for Linux User Guide
    PCoIP® Host Software for Linux User Guide TER1104006 Issue 7 PCoIP® Host Software for Linux User Guide Teradici Corporation #101-4621 Canada Way, Burnaby, BC V5G 4X8 Canada phone +1.604.451.5800 fax +1.604.451.5818 www.teradici.com The information contained in this documentation represents the current view of Teradici Corporation as of the date of publication. Because Teradici must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Teradici, and Teradici cannot guarantee the accuracy of any information presented after the date of publication. This document is for informational purposes only. TERADICI MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS DOCUMENT. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Teradici Corporation. Teradici may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Teradici, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property. Visit Notice of Intellectual Property Rights for more information. © 2000-2015 Teradici Corporation. All rights reserved. Teradici, PC-over-IP, and PCoIP are trademarks of Teradici Corporation and may be registered in the United States and/or other countries.
    [Show full text]
  • AEDIT Text Editor Iii Notational Conventions This Manual Uses the Following Conventions: • Computer Input and Output Appear in This Font
    Quick Contents Chapter 1. Introduction and Tutorial Chapter 2. The Editor Basics Chapter 3. Editing Commands Chapter 4. AEDIT Invocation Chapter 5. Macro Commands Chapter 6. AEDIT Variables Chapter 7. Calc Command Chapter 8. Advanced AEDIT Usage Chapter 9. Configuration Commands Appendix A. AEDIT Command Summary Appendix B. AEDIT Error Messages Appendix C. Summary of AEDIT Variables Appendix D. Configuring AEDIT for Other Terminals Appendix E. ASCII Codes Index AEDIT Text Editor iii Notational Conventions This manual uses the following conventions: • Computer input and output appear in this font. • Command names appear in this font. ✏ Note Notes indicate important information. iv Contents 1 Introduction and Tutorial AEDIT Tutorial ............................................................................................... 2 Activating the Editor ................................................................................ 2 Entering, Changing, and Deleting Text .................................................... 3 Copying Text............................................................................................ 5 Using the Other Command....................................................................... 5 Exiting the Editor ..................................................................................... 6 2 The Editor Basics Keyboard ......................................................................................................... 8 AEDIT Display Format ..................................................................................
    [Show full text]
  • Editores, Compilación Y Ejecución)
    Guía práctica de estudio 06: Entorno de C (editores, compilación y ejecución) Elaborado por: Ing. Laura Sandoval Montaño Juan Francisco De reza Trujillo Guía práctica de estudio 06: Entorno de C (editores, compilación y ejecución) Objetivo: Conocer y usar los ambientes y herramientas para el desarrollo y ejecución de programas en Lenguaje C, como editores y compiladores en diversos sistemas operativos. Actividades: . Utilizando un editor de GNU/Linux, crear un archivo de texto . Modificar/actualizar un archivo ya existente con un editor GNU/Linux. Crear, compilar y ejecutar un programa simple escrito en C en GNU/Linux . En algún entorno de desarrollo de Windows, crear, compilar y ejecutar un programa simple escrito en C. Introducción Un lenguaje de programación permite expresar una serie de instrucciones que podrán ser realizadas por una computadora. Unos de los lenguajes de programación mayormente difundidos es el lenguaje C. Éste es muy utilizado ya que la forma de dar instrucciones es muy cercana a lo que un humano podría abstraer, es decir, las instrucciones no son tal cual las que una computadora podría entender, para ello se necesitaría conocer a fondo el microprocesador, el sistema operativo entre otros aspectos. Por esta razón, C es conocido como un lenguaje de alto nivel, esto significa a que las instrucciones podrían ser entendidas fácilmente por un humano. En contraparte, un lenguaje de bajo nivel, son instrucciones que son cercanas a lo que la máquina puede entender y difícilmente pueden ser comprendidas por una persona que no tenga conocimientos de la máquina en que operarán. Algunos autores consideran al lenguaje C como un lenguaje de mediano nivel, ya que no es totalmente transparente sino tiene elementos que tienen que ver con la arquitectura de la máquina a la hora de programar.
    [Show full text]
  • A Brief History of UNIX File Systems
    A Brief History of UNIX File Systems Val Henson IBM, Inc. [email protected] Summary • Review of UNIX file system concepts • File system formats, 1974-2004 • File system comparisons and recommendations • Fun trivia • Questions and answers (corrections ONLY during talk) 1 VFS/vnode architecture • VFS: Virtual File System: common object-oriented interface to fs's • vnode: virtual node: abstract file object, includes vnode ops • All operations to fs's and files done through VFS/vnode in- terface • S.R. Kleiman, \Vnodes: An Architecture for Multiple File System Types in Sun UNIX," Summer USENIX 1986 2 Some Definitions superblock: fs summary, pointers to other information inode: on-disk structure containing information about a file indirect block: block containing pointers to other blocks metadata: everything that is not user data, including directory entries 3 Disk characteristics • Track - contiguous region, can be read at maximum speed • Seek time - time to move the head between different tracks • Rotational delay - time for part of track to move under head • Fixed per I/O overhead means bigger I/Os are better 4 In the beginning: System V FS (S5FS) (c. 1974) • First UNIX file system, referred to as \FS" • Disk layout: superblock, inodes, followed by everything else • 512-1024 byte block size, no fragments • Super simple - and super slow! 2-5% of raw disk bandwidth 5 Berkeley Fast File System (FFS or UFS) (c. 1984) • Metadata spread throughout the disk in \cylinder groups" • Block size 4KB minimum, frag size 1KB (to avoid 45% wasted space) • Physical
    [Show full text]
  • Modern Programming Languages CS508 Virtual University of Pakistan
    Modern Programming Languages (CS508) VU Modern Programming Languages CS508 Virtual University of Pakistan Leaders in Education Technology 1 © Copyright Virtual University of Pakistan Modern Programming Languages (CS508) VU TABLE of CONTENTS Course Objectives...........................................................................................................................4 Introduction and Historical Background (Lecture 1-8)..............................................................5 Language Evaluation Criterion.....................................................................................................6 Language Evaluation Criterion...................................................................................................15 An Introduction to SNOBOL (Lecture 9-12).............................................................................32 Ada Programming Language: An Introduction (Lecture 13-17).............................................45 LISP Programming Language: An Introduction (Lecture 18-21)...........................................63 PROLOG - Programming in Logic (Lecture 22-26) .................................................................77 Java Programming Language (Lecture 27-30)..........................................................................92 C# Programming Language (Lecture 31-34) ...........................................................................111 PHP – Personal Home Page PHP: Hypertext Preprocessor (Lecture 35-37)........................129 Modern Programming Languages-JavaScript
    [Show full text]
  • Unix Command Line; Editors
    Unix command line; editors Karl Broman Biostatistics & Medical Informatics, UW–Madison kbroman.org github.com/kbroman @kwbroman Course web: kbroman.org/AdvData My goal in this lecture is to convince you that (a) command-line-based tools are the things to focus on, (b) you need to choose a powerful, universal text editor (you’ll use it a lot), (c) you want to be comfortable and skilled with each. For your work to be reproducible, it needs to be code-based; don’t touch that mouse! Windows vs. Mac OSX vs. Linux Remote vs. Not 2 The Windows operating system is not very programmer-friendly. Mac OSX isn’t either, but under the hood, it’s just unix. Don’t touch the mouse! Open a terminal window and start typing. I do most of my work directly on my desktop or laptop. You might prefer to work remotely on a server, instead. But I can’t stand having any lag in looking at graphics. If you use Windows... Consider Git Bash (or Cygwin) or turn on the Windows subsystem for linux 3 Cygwin is an effort to get Unix command-line tools in Windows. Git Bash combines git (for version control) and bash (the unix shell); it’s simpler to deal with than Cygwin. Linux is now accessible in Windows 10, but you have to enable it. If you use a Mac... Consider Homebrew and iTerm2 Also the XCode command line tools 4 Homebrew is a packaging system; iTerm2 is a Terminal replacement. The XCode command line tools are a must for most unixy things on a Mac.
    [Show full text]
  • Getting to Grips with Unix and the Linux Family
    Getting to grips with Unix and the Linux family David Chiappini, Giulio Pasqualetti, Tommaso Redaelli Torino, International Conference of Physics Students August 10, 2017 According to the booklet At this end of this session, you can expect: • To have an overview of the history of computer science • To understand the general functioning and similarities of Unix-like systems • To be able to distinguish the features of different Linux distributions • To be able to use basic Linux commands • To know how to build your own operating system • To hack the NSA • To produce the worst software bug EVER According to the booklet update At this end of this session, you can expect: • To have an overview of the history of computer science • To understand the general functioning and similarities of Unix-like systems • To be able to distinguish the features of different Linux distributions • To be able to use basic Linux commands • To know how to build your own operating system • To hack the NSA • To produce the worst software bug EVER A first data analysis with the shell, sed & awk an interactive workshop 1 at the beginning, there was UNIX... 2 ...then there was GNU 3 getting hands dirty common commands wait till you see piping 4 regular expressions 5 sed 6 awk 7 challenge time What's UNIX • Bell Labs was a really cool place to be in the 60s-70s • UNIX was a OS developed by Bell labs • they used C, which was also developed there • UNIX became the de facto standard on how to make an OS UNIX Philosophy • Write programs that do one thing and do it well.
    [Show full text]
  • Unix/Linux Command Reference
    Unix/Linux Command Reference .com File Commands System Info ls – directory listing date – show the current date and time ls -al – formatted listing with hidden files cal – show this month's calendar cd dir - change directory to dir uptime – show current uptime cd – change to home w – display who is online pwd – show current directory whoami – who you are logged in as mkdir dir – create a directory dir finger user – display information about user rm file – delete file uname -a – show kernel information rm -r dir – delete directory dir cat /proc/cpuinfo – cpu information rm -f file – force remove file cat /proc/meminfo – memory information rm -rf dir – force remove directory dir * man command – show the manual for command cp file1 file2 – copy file1 to file2 df – show disk usage cp -r dir1 dir2 – copy dir1 to dir2; create dir2 if it du – show directory space usage doesn't exist free – show memory and swap usage mv file1 file2 – rename or move file1 to file2 whereis app – show possible locations of app if file2 is an existing directory, moves file1 into which app – show which app will be run by default directory file2 ln -s file link – create symbolic link link to file Compression touch file – create or update file tar cf file.tar files – create a tar named cat > file – places standard input into file file.tar containing files more file – output the contents of file tar xf file.tar – extract the files from file.tar head file – output the first 10 lines of file tar czf file.tar.gz files – create a tar with tail file – output the last 10 lines
    [Show full text]
  • 101 Useful Linux Commands - Haydenjames.Io
    101 Useful Linux Commands - haydenjames.io Some of these commands require elevated permissions (sudo) to run. Enjoy! 1. Execute the previous command used: !! 2. Execute a previous command starting with a specific letter. Example: !s 3. Short way to copy or backup a file before you edit it. For example, copy nginx.conf cp nginx.conf{,.bak} 4. Toggle between current directory and last directory cd - 5. Move to parent (higher level) directory. Note the space! cd .. 6. Go to home directory cd ~ 7. Go to home directory cd $HOME 8. Go to home directory (when used alone) cd 9. Set permissions to 755. Corresponds to these permissions: (-rwx-r-x-r-x), arranged in this sequence: (owner-group-other) chmod 755 <filename> 10. Add execute permission to all users. chmod a+x <filename> 11. Changes ownership of a file or directory to . chown <username> 12. Make a backup copy of a file (named file.backup) cp <file> <file>.backup 13. Copy file1, use it to create file2 cp <file1> <file2> 14. Copy directory1 and all its contents (recursively) into directory2 cp -r <directory1> <directory2>/ 15. Display date date 16. Zero the sdb drive. You may want to use GParted to format the drive afterward. You need elevated permissions to run this (sudo). dd if=/dev/zero of=/dev/sdb 17. Display disk space usage df -h 18. Take detailed messages from OS and input to text file dmesg>dmesg.txt 19. Display a LOT of system information. I usually pipe output to less. You need elevated permissions to run this (sudo).
    [Show full text]
  • Linking + Libraries
    LinkingLinking ● Last stage in building a program PRE- COMPILATION ASSEMBLY LINKING PROCESSING ● Combining separate code into one executable ● Linking done by the Linker ● ld in Unix ● a.k.a. “link-editor” or “loader” ● Often transparent (gcc can do it all for you) 1 LinkingLinking involves...involves... ● Combining several object modules (the .o files corresponding to .c files) into one file ● Resolving external references to variables and functions ● Producing an executable file (if no errors) file1.c file1.o file2.c gcc file2.o Linker Executable fileN.c fileN.o Header files External references 2 LinkingLinking withwith ExternalExternal ReferencesReferences file1.c file2.c int count; #include <stdio.h> void display(void); Compiler extern int count; int main(void) void display(void) { file1.o file2.o { count = 10; with placeholders printf(“%d”,count); display(); } return 0; Linker } ● file1.o has placeholder for display() ● file2.o has placeholder for count ● object modules are relocatable ● addresses are relative offsets from top of file 3 LibrariesLibraries ● Definition: ● a file containing functions that can be referenced externally by a C program ● Purpose: ● easy access to functions used repeatedly ● promote code modularity and re-use ● reduce source and executable file size 4 LibrariesLibraries ● Static (Archive) ● libname.a on Unix; name.lib on DOS/Windows ● Only modules with referenced code linked when compiling ● unlike .o files ● Linker copies function from library into executable file ● Update to library requires recompiling program 5 LibrariesLibraries ● Dynamic (Shared Object or Dynamic Link Library) ● libname.so on Unix; name.dll on DOS/Windows ● Referenced code not copied into executable ● Loaded in memory at run time ● Smaller executable size ● Can update library without recompiling program ● Drawback: slightly slower program startup 6 LibrariesLibraries ● Linking a static library libpepsi.a /* crave source file */ … gcc ..
    [Show full text]
  • Oregon Statewide Payroll Application ‐ Paystub Pay and Leave Codes
    Oregon Statewide Payroll Application ‐ Paystub Pay and Leave Codes PAYSTUB PAY AND LEAVE CODES Pay Type Code Paystub Description Detail Description ABL OSPOA BUSINESS Leave used when conducting OSPOA union business by authorized individuals. Leave must be donated from employees within the bargaining unit. A donation/use maximum is established by contract. AD ADMIN LV Paid leave time granted to compensate for work performed outside normal work hours by Judicial Department employees who are ineligible for overtime. (Agency Policy) ALC ASST LGL DIF 5% Differential for Assistant Legal Counsel at Judicial Department. (PPDB code) ANA ALLW N/A PLN Code used to record taxable cash value of non-cash clothing allowance or other employee fringe benefit. (P050) ANC NRS CRED Nurses credentialing per CBA ASA APPELATE STF Judicial Department Appellate Judge differential. (PPDB code) AST ADDL STRAIGHTTIME Additional straight time hours worked within same period that employee recorded sick, holiday, or other regular paid leave hours. Refer to Statewide Policy or Collective Bargaining Agreement. Hours not used in leave and benefit calculations. AT AWARD TM TKN Paid leave for Judicial Department and Public Defense Service employees as years of service award. (Agency Policy) AW ASSUMED WAGES-UNPD Code used to record and track hours of volunteer non-employee workers. Does not VOL HR generate pay. (P050) BAV BP/AWRD VALU Code used to record the taxable cash value of a non-cash award or bonus granted through an agency recognition program. Not PERS subject. (P050 code) BBW BRDG/BM/WELDR Certified Bridge/Boom/Welder differential (PPDB code) BCD BRD CERT DIFF Board Certification Differential for Nurse Practitioners at the Oregon State Hospital of five percent (5%) for all Nurse Practitioners who hold a Board certification related to their assignment.
    [Show full text]