book

bash Idioms

by Carl Albing, JP Vossen

March 2022

Intermediate to advanced

167 pages

3h 46m

English

O'Reilly Media, Inc.

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Running bashbash on Macbash in ContainersRevision ControlHello WorldConventions Used in This BookUsing Code ExamplesO’Reilly Online LearningHow to Contact UsAcknowledgmentsbashReviewersO’ReillyFrom CarlFrom JP
The Big “if”Or ELSE…More than OneMore than One AgainDon’t Do ThisStyle and Readability: Recap
Looping ConstructsExplicit ValuesSimilar to PythonQuotes and SpacesDeveloping and Testing for Loopswhile and untilStyle and Readability: Recap
Make Your CaseA Realistic Use CaseMotivationOur ScriptWrapper ScriptsOne More TwistStyle and Readability: Recap
Variable ReferenceParameter ExpansionShorthand for basenamePath or Prefix RemovalShorthand for dirname or Suffix RemovalOther ModifiersConditional SubstitutionsDefault ValuesComma-Separated ListsModified Value$RANDOMCommand SubstitutionStyle and Readability: Recap
ArithmeticNo Parentheses NeededCompound CommandsStyle and Readability: Recap
Calling FunctionsDefining FunctionsFunction ParametersFunction Return ValuesLocal VariablesFunction Special CasesTime for printfPOSIX OutputGetting or Using the Date and Timeprintf for Reuse or DebuggingStyle and Readability: Recap
CommonalitiesListsHashesA Simple Word Count ExampleStyle and Readability: Recap
Your First ArgumentHaving OptionsParsing OptionsLong ArgumentsHELP!Debug and VerboseVersionStyle and Readability: Recap
Reading FilesreadmapfileBrute ForceFiddling with $IFS for Fun and Profit, to Read FilesPretend FilesDrop-in DirectoriesUsing a LibraryShebang!Unofficial bash Strict ModeExit CodesIt’s a Trap!Here-Documents and Here-StringsAre We Interactive?Summary

Promptsbash Time ZoneGetting User InputreadpauseselectAliasesFunctionsLocal VariablesReadline HacksUsing logger from bashHandling JSON with jqGrepping the Process ListRotating Old FilesEmbedded Documentationbash Debuggingbash Unit TestingSummary
ReadabilityCommentsNamesFunctionsQuotingLayoutSyntaxOtherScript TemplateOther Style Guidesbash LinterSummary
ReadabilityCommentsNamesFunctionsQuotingLayoutSyntaxOtherScript Template

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About the Authors

Carl Albing is a professor, researcher, and software engineer with a breadth of industry experience. A coauthor of O’Reilly’s bash Cookbook and Cybersecurity Ops with bash, as well as the author of O’Reilly’s “Great bash” video, Carl has worked in software (using bash and many other languages) for companies large and small, across a variety of industries. He has a BA in mathematics, a master’s in international management (MIM), and a PhD in computer science.

JP Vossen has been working with computers since the early 80s and has been in the IT industry since the early 90s, specializing in information security since the late 90s. He’s been fascinated with scripting and automation since he first understood what an autoexec.bat was, and was delighted to discover the power and flexibility of bash and GNU on Linux in the mid-90s. He has previously written for Information Security Magazine and SearchSecurity, among other publications. On those few occasions when he’s not in front of a computer, he is usually taking something apart, putting something together, or both.