book

Pro Bash Programming : Scripting the GNU/Linux Shell, Second Edition

by Chris F. A. Johnson, Jayant Varma

June 2015

Beginner to intermediate

256 pages

4h 48m

English

Apress

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The CodeThe FileThe Naming of ScriptsSelecting a Directory for the ScriptCreating the File and Running the ScriptChoosing and Using a Text EditorBuilding a Better “Hello, World!”SummaryCommandsConceptsVariablesExercises
Parameter and VariablesPositional ParametersSpecial*@#0$?_!- ParametersVariablesArguments and Optionsecho, and Why You Should Avoid Itprintf: Formatting and Printing DataEscape SequencesFormat SpecifiersWidth SpecificationPrinting to a VariableLine ContinuationStandard Input /Output Streams and RedirectionRedirection: >, >>, and <Reading InputPipelinesCommand SubstitutionSummaryCommandsConceptsExercises

Exit StatusTesting an Expressiontest, a.k.a. [ … ][[ … ]]: Evaluate an Expression(( … )): Evaluate an Arithmetic ExpressionConditional ExecutionifConditional Operators, & and ||caseLoopingwhileuntilforbreakcontinueSummaryCommandsConceptsExercises
QuotingBrace ExpansionTilde ExpansionParameter and Variable ExpansionArithmetic ExpansionCommand SubstitutionWord SplittingPathname ExpansionProcess SubstitutionParsing OptionsSummaryCommandsExercises
The Naming of VariablesThe Scope of a Variable: Can You See It from Here?Shell VariablesParameter ExpansionBourne ShellPOSIX ShellBashBash-4.0Positional ParametersArraysInteger-Indexed ArraysAssociative ArraysSummaryCommandsConcepts
Definition SyntaxCompound CommandsGetting ResultsSet Different Exit CodesPrint the ResultPlace Results in One or More VariablesFunction LibrariesUsing Functions from LibrariesSample ScriptSummaryCommandsExercises
ConcatenationRepeat Character to a Given LengthProcessing Character by CharacterReversalCase ConversionComparing Contents Without Regard to CaseCheck for Valid Variable NameInsert One String into AnotherExamplesOverlayExamplesTrim Unwanted CharactersExamplesIndexSummaryCommandsFunctionsExercises
Reading a FileExternal CommandscatheadtouchlscutwcRegular ExpressionsgrepsedawkFile Name Expansion OptionsnullglobfailglobdotglobextglobnocaseglobglobstarSummaryShell OptionsExternal CommandsExercises
help, Display Information About Built-In Commandstime, Print Time Taken for Execution of a Commandread, Read a Line from an Input Stream-r, Read Backslashes Literally-e, Get Input with the readline Library-a, Read Words into an Array-d DELIM, Read Until DELIM Instead of a Newline-n NUM, Read a Maximum of NUM Characters-s, Do Not Echo Input Coming from a Terminal-p PROMPT:, Output PROMPT Without a Trailing Newline-t TIMEOUT, Only Wait TIMEOUT Seconds for Complete Input-u FD: Read from File Descriptor FD Instead of the Standard Input-i TEXT, Use TEXT as the Initial Text for Readlineeval, Expand Arguments and Execute Resulting CommandPoor Man’s ArraysSetting Multiple Variables from One Commandtype, Display Information About Commandsbuiltin, Execute a Built-In Commandcommand, Execute a Command or Display Information About Commandspwd, Print the Current Working Directoryunalias, Remove One or More AliasesDeprecated Built-InsDynamically Loadable Built-InsSummaryCommands and Reserved WordsDeprecated CommandsExercise
Prevention Is Better Than CureStructure Your ProgramsDocument Your CodeFormat Your Code ConsistentlyThe K.I.S.S. PrincipleTest as You GoDebugging a ScriptSummaryExercises
Manipulating the Directory StackcdpdcdmmenuFilesystem Functionsllsrcp, mvmdMiscellaneous Functionspr1calcManaging Man PagessmansuskGamesThe fifteen PuzzleSummaryExercises
Defining VariablesCommand-Line Options and ArgumentsMenusQ&A DialogueConfiguration FilesScripts with Several NamesEnvironment VariablesAll Together NowScript InformationDefault ConfigurationScreen VariablesFunction DefinitionsParse Command-Line OptionsBits and PiecesSummaryExercises
ArraysHoles in an Indexed ArrayUsing an Array for SortingTwo-Dimensional GridsData File FormatsLine-Based RecordsBlock File FormatsSummaryExercises
Teletypewriter vs. CanvasStretching the CanvasCommand Sequence IntroducerPriming the CanvasMoving the CursorChanging Rendition Modes and ColorsPlacing a Block of Text on the ScreenScrolling TextRolling DiceSummaryExercises
Single-Key EntryFunction Library, key-funcsHistory in ScriptsSanity CheckingForm EntryReading the MouseSummaryExercises
BASHBASHPIDBASH_ALIASESBASH_ARGCBASH_ARGVBASH_CMDSBASH_COMMANDBASH_EXECUTION_STRINGBASH_LINENOBASH_REMATCHBASH_SOURCEBASH_SUBSHELLBASH_VERSINFOBASH_VERSIONCOMP_CWORDCOMP_KEYCOMP_LINECOMP_POINTCOMP_TYPECOMP_WORDBREAKSCOMP_WORDSDIRSTACKEUIDFUNCNAMEGROUPSHISTCMDHOSTNAMEHOSTTYPELINENOMACHTYPEOLDPWDOPTARGOPTINDOSTYPEPIPESTATUSPPIDPWDRANDOMREPLYSECONDSSHELLOPTSSHLVLUIDBASH_ENVCDPATHCOLUMNSCOMPREPLYEMACSFCEDITFIGNOREGLOBIGNOREHISTCONTROLHISTFILEHISTFILESIZEHISTIGNOREHISTSIZEHISTTIMEFORMATHOMEHOSTFILEIFSIGNOREEOFINPUTRCLANGLC_ALLLC_COLLATELC_CTYPELC_MESSAGESLC_NUMERICLINESMAILMAILCHECKMAILPATHOPTERRPATHPOSIXLY_CORRECTPROMPT_COMMANDPROMPT_DIRTRIMPS1PS2PS3PS4SHELLTIMEFORMATTMOUTTMPDIRauto_resumehistchars