Hjem

Preface; Who Should Read This Book; About This Book; Conventions Used in This Book; Using Code Examples; We''d Like to Hear from You; Safari® Enabled; Acknowledgments;
Chapter 1: Beginning bash; 0 Why bash?; 0 The bash Shell;
1.1 Decoding the Prompt;
1.2 Showing Where You Are;
1.3 Finding and Running Commands;
1.4 Getting Information About Files;
1.5 Showing All Hidden (dot) Files in the Current Directory;
1.6 Using Shell Quoting;
1.7 Using or Replacing Built-ins and External Commands;
1.8 Determining If You Are Running Interactively;
1.9 Setting bash As Your Default Shell;
1.10 Getting bash for Linux;
1.11 Getting bash for xBSD;
1.12 Getting bash for Mac OS X;
1.13 Getting bash for Unix;
1.14 Getting bash for Windows;
1.15 Getting bash Without Getting bash;
1.16 Learning More About bash Documentation;
Chapter 2: Standard Output;
2.1 Writing Output to the Terminal/Window;
2.2 Writing Output but Preserving Spacing;
2.3 Writing Output with More Formatting Control;
2.4 Writing Output Without the Newline;
2.5 Saving Output from a Command;
2.6 Saving Output to Other Files;
2.7 Saving Output from the ls Command;
2.8 Sending Both Output and Error Messages to Different Files;
2.9 Sending Both Output and Error Messages to the Same File;
2.10 Appending Rather Than Clobbering Output;
2.11 Using Just the Beginning or End of a File;
2.12 Skipping a Header in a File;
2.13 Throwing Output Away;
2.14 Saving or Grouping Output from Several Commands;
2.15 Connecting Two Programs by Using Output As Input;
2.16 Saving a Copy of Output Even While Using It As Input;
2.17 Connecting Two Programs by Using Output As Arguments;
2.18 Using Multiple Redirects on One Line;
2.19 Saving Output When Redirect Doesn''t Seem to Work;
2.20 Swapping STDERR and STDOUT;
2.21 Keeping Files Safe from Accidental Overwriting;
2.22 Clobbering a File on Purpose;
Chapter 3: Standard Input;
3.1 Getting Input from a File;
3.2 Keeping Your Data with Your Script;
3.3 Preventing Weird Behavior in a Here-Document;
3.4 Indenting Here-Documents;
3.5 Getting User Input;
3.6 Getting Yes or No Input;
3.7 Selecting from a List of Options;
3.8 Prompting for a Password;
Chapter 4: Executing Commands;
4.1 Running Any Executable;
4.2 Telling If a Command Succeeded or Not;
4.3 Running Several Commands in Sequence;
4.4 Running Several Commands All at Once;
4.5 Deciding Whether a Command Succeeds;
4.6 Using Fewer if Statements;
4.7 Running Long Jobs Unattended;
4.8 Displaying Error Messages When Failures Occur;
4.9 Running Commands from a Variable;
4.10 Running All Scripts in a Directory;
Chapter 5: Basic Scripting: Shell Variables;
5.1 Documenting Your Script;
5.2 Embedding Documentation in Shell Scripts;
5.3 Promoting Script Readability;
5.4 Separating Variable Names from Surrounding Text;
5.5 Exporting Variables;
5.6 Seeing All Variable Values;
5.7 Using Parameters in a Shell Script;
5.8 Looping Over Arguments Passed to a Script;
5.9 Handling Parameters with Blanks;
5.10 Handling Lists of Parameters with Blanks;
5.11 Counting Arguments;
5.12 Consuming Arguments;
5.13 Getting Default Values;
5.14 Setting Default Values;
5.15 Using null As a Valid Default Value;
5.16 Using More Than Just a Constant String for Default;
5.17 Giving an Error Message for Unset Parameters;
5.18 Changing Pieces of a String;
5.19 Using Array Variables;
Chapter 6: Shell Logic and Arithmetic;
6.1 Doing Arithmetic in Your Shell Script;
6.2 Branching on Conditions;
6.3 Testing for File Characteristics;
6.4 Testing for More Than One Thing;
6.5 Testing for String Characteristics;
6.6 Testing for Equal;
6.7 Testing with Pattern Matches;
6.8 Testing with Regular Expressions;
6.9 Changing Behavior with Redirections;
6.10 Looping for a While;
6.11 Looping with a read;
6.12 Looping with a Count;
6.13 Looping with Floating-Point Values;
6.14 Branching Many Ways;
6.15 Parsing Command-Line Arguments;
6.16 Creating Simple Menus;
6.17 Changing the Prompt on Simple Menus;
6.18 Creating a Simple RPN Calculator;
6.19 Creating a Command-Line Calculator;
Chapter 7: Intermediate Shell Tools I;
7.1 Sifting Through Files for a String;
7.2 Getting Just the Filename from a Search;
7.3 Getting a Simple True/False from a Search;
7.4 Searching for Text While Ignoring Case;
7.5 Doing a Search in a Pipeline;
7.6 Paring Down What the Search Finds;
7.7 Searching with More Complex Patterns;
7.8 Searching for an SSN;
7.9 Grepping Compressed Files;
7.10 Keeping Some Output, Discarding the Rest;
7.11 Keeping Only a Portion of a Line of Output;
7.12 Reversing the Words on Each Line;
7.13 Summing a List of Numbers;
7.14 Counting String Values;
7.15 Showing Data As a Quick and Easy Histogram;
7.16 Showing a Paragraph of Text After a Found Phrase;
Chapter 8: Intermediate Shell Tools II;
8.1 Sorting Your Output;
8.2 Sorting Numbers;
8.3 Sorting IP Addresses;
8.4 Cutting Out Parts of Your Output;
8.5 Removing Duplicate Lines;
8.6 Compressing Files;
8.7 Uncompressing Files;
8.8 Checking a tar Archive for Unique Directories;
8.9 Translating Characters;
8.10 Converting Uppercase to Lowercase;
8.11 Converting DOS Files to Linux Format;
8.12 Removing Smart Quotes;
8.13 Counting Lines, Words, or Characters in a File;
8.14 Rewrapping Paragraphs;
8.15 Doing More with less;
Chapter 9: Finding Files: find, locate, slocate;
9.1 Finding All Your MP3 Files;
9.2 Handling Filenames Containing Odd Characters;
9.3 Speeding Up Operations on Found Files;
9.4 Finding Files Across Symbolic Links;
9.5 Finding Files Irrespective of Case;
9.6 Finding Files by Date;
9.7 Finding Files by Type;
9.8 Finding Files by Size;
9.9 Finding Files by Content;
9.10 Finding Existing Files and Content Fast;
9.11 Finding a File Using a List of Possible Locations;
Chapter 10: Additional Features for Scripting;
10.1 "Daemon-izing" Your Script;
10.2 Reusing Code with Includes and Sourcing;
10.3 Using Configuration Files in a Script;
10.4 Defining Functions;
10.5 Using Functions: Parameters and Return Values;
10.6 Trapping Interrupts;
10.7 Redefining Commands with alias;
10.8 Avoiding Aliases, Functions;
Chapter 11: Working with Dates and Times;
11.1 Formatting Dates for Display;
11.2 Supplying a Default Date;
11.3 Automating Date Ranges;
11.4 Converting Dates and Times to Epoch Seconds;
11.5 Converting Epoch Seconds to Dates and Times;
11.6 Getting Yesterday or Tomorrow with Perl;
11.7 Figuring Out Date and Time Arithmetic;
11.8 Handling Time Zones, Daylight Saving Time, and Leap Years;
11.9 Using date and cron to Run a Script on the Nth Day;
Chapter 12: End-User Tasks As Shell Scripts;
12.1 Starting Simple by Printing Dashes;
12.2 Viewing Photos in an Album;
12.3 Loading Your MP3 Player;
12.4 Burning a CD;
12.5 Comparing Two Documents;
Chapter 13: Parsing and Similar Tasks;
13.1 Parsing Arguments for Your Shell Script;
13.2 Parsing Arguments with Your Own Error Messages;
13.3 Parsing Some HTML;
13.4 Parsing Output into an Array;
13.5 Parsing Output with a Function Call;
13.6 Parsing Text with a read Statement;
13.7 Parsing with read into an Array;
13.8 Getting Your Plurals Right;
13.9 Taking It One Character at a Time;
13.10 Cleaning Up an SVN Source Tree;
13.11 Setting Up a Database with MySQL;
13.12 Isolating Specific Fields in Data;
13.13 Updating Specific Fields in Data Files;
13.14 Trimming Whitespace;
13.15 Compressing Whitespace;
13.16 Processing Fixed-Length Records;
13.17 Processing Files with No Line Breaks;
13.18 Converting a Data File to CSV;
13.19 Parsing a CSV Data File;
Chapter 14: Writing Secure Shell Scripts;
14.1 Avoiding Common Security Problems;
14.2 Avoiding Interpreter Spoofing;
14.3 Setting a Secure $PATH;
14.4 Clearing All Aliases;
14.5 Clearing the Command Hash;
14.6 Preventing Core Dumps;
14.7 Setting a Secure $IFS;
14.8 Setting a Secure umask;
14.9 Finding World-Writable Directories in Your $PATH;
14.10 Adding the Current Directory to the $PATH;
14.11 Using Secure Temporary Files;
14.12 Validating Input;
14.13 Setting Permissions;
14.14 Leaking Passwords into the Process List;
14.15 Writing setuid or setgid Scripts;
14.16 Restricting Guest Users;
14.17 Using chroot Jails;
14.18 Running As a Non-root User;
14.19 Using sudo More Securely;
14.20 Using Passwords in Scripts;
14.21 Using SSH Without a Password;
14.22 Restricting SSH Commands;
14.23 Disconnecting Inactive Sessions;
Chapter 15: Advanced Scripting;
15.1 Finding bash Portably for #!;
15.2 Setting a POSIX $PATH;
15.3 Developing Portable Shell Scripts;
15.4 Testing Scripts in VMware;
15.5 Using for Loops Portably;
15.6 Using echo Portably;
15.7 Splitting Output Only When Necessary;
15.8 Viewing Output in Hex;
15.9 Using bash Net-Redirection;
15.10 Finding My IP Address;
15.11 Getting Input from Another Machine;
15.12 Redirecting Output for the Life of a Script;
15.13 Working Around "argument list too long" Errors;
15.14 Logging to syslog from Your Script;
15.15 Sending Email from Your Script;
15.16 Automating a Process Using Phases;
Chapter 16: Configuring and Customizing bash;
16.1 bash Startup Options;
16.2 Customizing Your Prompt;
16.3 Change Your $PATH Permanently;
16.4 Change Your $PATH Temporarily;
16.5 Setting Your $CDPATH;
16.6 Shortening or Changing Command Names;
16.7 Adjusting Shell Behavior and Environment;
16.8 Adjusting readline Behavior Using
.inputrc;
16.9 Keeping a Private Stash of Utilities by Adding ~/bin;
16.10 Using Secondary Prompts: $PS2, $PS3, $PS4;
16.11 Synchronizing Shell History Between Sessions;
16.12 Setting Shell History Options; 13 Creating a Better cd Command;
16.14 Creating and Changing into a New Directory in One Step;
16.15 Getting to the Bottom of Things;
16.16 Adding New Features to bash Using Loadable Built-ins;
16.17 Improving Programmable Completion;
16.18 Using Initialization Files Correctly;
16.19 Creating Self-Contained, Portable RC Files;
16.20 Getting Started with a Custom Configuration;
Chapter 17: Housekeeping and Administrative Tasks;
17.1 Renaming Many Files;
17.2 Using GNU Texinfo and Info on Linux;
17.3 Unzipping Many ZIP Files;
17.4 Recovering Disconnected Sess