Windows Powershell in Action, Second Edition

contents......Page 5
PART 1 Learning PowerShell......Page 17
 1 Welcome to PowerShell......Page 18
  1.1 What is PowerShell?......Page 20
   1.1.1 Shells, command lines, and scripting languages......Page 21
   1.1.2 Why a new shell? Why now?......Page 22
   1.1.3 The last mile problem......Page 23
   1.2.1 Learning from history......Page 24
   1.2.2 Leveraging .NET......Page 25
   1.3.1 Reviewing object-oriented programming......Page 26
  1.4 Up and running with PowerShell......Page 28
   1.4.3 The PowerShell console host......Page 29
   1.4.4 The PowerShell Integrated Scripting Environment......Page 32
   1.4.5 Command completion......Page 35
   1.5.1 Navigation and basic operations......Page 37
   1.5.2 Basic expressions and variables......Page 38
   1.5.3 Processing data......Page 40
   1.5.4 Flow-control statements......Page 45
   1.5.5 Scripts and functions......Page 46
   1.5.6 Remoting and the Universal Execution Model......Page 47
  1.6 Summary......Page 50
 2 Foundations of PowerShell......Page 51
  2.1 Getting a sense of the PowerShell language......Page 52
   2.2.2 Commands and cmdlets......Page 53
   2.2.3 Command categories......Page 57
  2.3 Aliases and elastic syntax......Page 62
  2.4 Parsing and PowerShell......Page 65
   2.4.2 Quoting......Page 66
   2.4.3 Expression-mode and command-mode parsing......Page 69
   2.4.4 Statement termination......Page 71
   2.4.5 Comment syntax in PowerShell......Page 73
  2.5 How the pipeline works......Page 75
   2.5.1 Pipelines and streaming behavior......Page 76
   2.5.2 Parameters and parameter binding......Page 77
   2.6.1 The formatting cmdlets......Page 79
   2.6.2 The outputter cmdlets......Page 82
  2.7 Summary......Page 85
  3.1 Type management in the wild, wild West......Page 87
   3.1.1 PowerShell: a type-promiscuous language......Page 88
   3.1.2 The type system and type adaptation......Page 90
   3.2.1 String literals......Page 92
   3.2.2 Numbers and numeric literals......Page 97
   3.3.1 Creating and inspecting hashtables......Page 100
   3.3.2 Modifying and manipulating hashtables......Page 103
   3.3.3 Hashtables as reference types......Page 105
   3.4.1 Collecting pipeline output as an array......Page 106
   3.4.3 Polymorphism in arrays......Page 107
   3.4.4 Arrays as reference types......Page 108
   3.4.5 Singleton arrays and empty arrays......Page 109
   3.5.1 Type name aliases......Page 111
   3.5.2 Generic type literals......Page 113
   3.5.3 Accessing static members with type literals......Page 114
   3.6.1 How type conversion works......Page 116
   3.6.2 PowerShell’s type-conversion algorithm......Page 119
   3.6.3 Special type conversions in parameter binding......Page 122
  3.7 Summary......Page 124
 4 Operators and expressions......Page 125
  4.1 Arithmetic operators......Page 127
   4.1.1 The addition operator......Page 128
   4.1.2 The multiplication operator......Page 131
   4.1.3 Subtraction, division, and the modulus operator......Page 132
  4.2 The assignment operators......Page 134
   4.2.1 Multiple assignments......Page 135
   4.2.2 Multiple assignments with type qualifiers......Page 136
   4.2.3 Assignment operations as value expressions......Page 138
  4.3 Comparison operators......Page 139
   4.3.1 Scalar comparisons......Page 140
   4.3.2 Comparisons and case sensitivity......Page 142
   4.3.3 Using comparison operators with collections......Page 144
  4.4 Pattern matching and text manipulation......Page 146
   4.4.1 Wildcard patterns and the -like operator......Page 147
   4.4.2 Regular expressions......Page 148
   4.4.3 The -match operator......Page 149
   4.4.4 The -replace operator......Page 152
   4.4.5 The -join operator......Page 154
   4.4.6 The -split operator......Page 158
  4.5 Logical and bitwise operators......Page 163
  4.6 Summary......Page 165
 5 Advanced operators and variables......Page 166
  5.1 Operators for working with types......Page 167
  5.2 The unary operators......Page 169
  5.3 Grouping and subexpressions......Page 172
   5.3.1 Subexpressions $( ... )......Page 174
   5.3.2 Array subexpressions @( ... )......Page 175
   5.4.1 The comma operator......Page 177
   5.4.2 The range operator......Page 180
   5.4.3 Array indexing and slicing......Page 182
   5.4.4 Using the range operator with arrays......Page 185
   5.4.5 Working with multidimensional arrays......Page 186
  5.5 Property and method operators......Page 188
   5.5.1 The dot operator......Page 189
   5.5.2 Static methods and the double-colon operator......Page 192
   5.5.3 Indirect method invocation......Page 193
  5.6 The format operator......Page 194
  5.7 Redirection and the redirection operators......Page 196
  5.8 Working with variables......Page 199
   5.8.1 Creating variables......Page 200
   5.8.2 Variable name syntax......Page 201
   5.8.3 Working with the variable cmdlets......Page 203
   5.8.4 Splatting a variable......Page 208
  5.9 Summary......Page 211
 6 Flow control in scripts......Page 213
  6.1 The conditional statement......Page 215
   6.2.1 The while loop......Page 218
   6.2.2 The do-while loop......Page 219
   6.2.3 The for loop......Page 220
   6.2.4 The foreach loop......Page 222
  6.3 Labels, break, and continue......Page 227
   6.4.1 Basic use of the switch statement......Page 230
   6.4.2 Using wildcard patterns with the switch statement......Page 231
   6.4.3 Using regular expressions with the switch statement......Page 232
   6.4.4 Processing files with the switch statement......Page 236
   6.4.5 Using the $switch loop enumerator in the switch statement......Page 237
   6.5.1 The ForEach-Object cmdlet......Page 238
   6.5.2 The Where-Object cmdlet......Page 243
  6.6 Statements as values......Page 246
  6.7 A word about performance......Page 248
  6.8 Summary......Page 249
 7 PowerShell functions......Page 251
   7.1.1 Passing arguments using $args......Page 252
   7.1.2 Example functions: ql and qs......Page 254
   7.1.3 Simplifying $args processing with multiple assignment......Page 255
  7.2 Declaring formal parameters for a function......Page 256
   7.2.1 Mixing named and positional parameters......Page 257
   7.2.2 Adding type constraints to parameters......Page 258
   7.2.3 Handling variable numbers of arguments......Page 260
   7.2.4 Initializing function parameters with default values......Page 261
   7.2.6 Using switch parameters to define command switches......Page 263
   7.2.7 Switch parameters vs. Boolean parameters......Page 267
  7.3 Returning values from functions......Page 272
   7.3.1 Debugging problems in function output......Page 274
   7.3.2 The return statement......Page 277
  7.4 Using simple functions in a pipeline......Page 278
   7.4.1 Filters and functions......Page 280
   7.4.2 Functions with begin, process, and end blocks......Page 281
  7.5 Managing function definitions in a session......Page 282
  7.6 Variable scoping in functions......Page 284
   7.6.1 Declaring variables......Page 285
   7.6.2 Using variable scope modifiers......Page 287
  7.7 Summary......Page 288
 8 Advanced functions and scripts......Page 290
   8.1.1 Script execution policy......Page 291
   8.1.2 Passing arguments to scripts......Page 293
   8.1.3 Exiting scripts and the exit statement......Page 295
   8.1.4 Scopes and scripts......Page 296
   8.1.5 Managing your scripts......Page 299
   8.1.6 Running PowerShell scripts from other applications......Page 300
  8.2 Writing advanced functions and scripts......Page 302
   8.2.1 Specifying script and function attributes......Page 303
   8.2.2 The CmdletBinding attribute......Page 304
   8.2.3 The OutputType attribute......Page 308
   8.2.4 Specifying parameter attributes......Page 311
   8.2.5 Creating parameter aliases with the Alias attribute......Page 318
   8.2.6 Parameter validation attributes......Page 320
  8.3 Dynamic parameters and dynamicParam......Page 326
   8.3.1 Steps for adding a dynamic parameter......Page 327
  8.4 Documenting functions and scripts......Page 329
   8.4.2 Creating manual help content......Page 330
   8.4.3 Comment-based help......Page 331
   8.4.4 Tags used in documentation comments......Page 333
  8.5 Summary......Page 336
 9 Using and authoring modules......Page 337
  9.1 The role of a module system......Page 338
   9.1.2 Module mashups: composing an application......Page 339
  9.2 Module basics......Page 340
   9.2.2 Modules are single-instance objects......Page 341
   9.3.1 Finding modules on the system......Page 342
   9.3.2 Loading a module......Page 346
   9.3.3 Removing a loaded module......Page 350
  9.4 Writing script modules......Page 352
   9.4.1 A quick review of scripts......Page 353
   9.4.2 Turning a script into a module......Page 355
   9.4.3 Controlling member visibility with Export-ModuleMember......Page 358
   9.4.4 Installing a module......Page 362
   9.4.5 How scopes work in script modules......Page 363
   9.4.6 Nested modules......Page 365
  9.5 Binary modules......Page 368
   9.5.1 Binary modules vs. snap-ins......Page 369
   9.5.2 Creating a binary module......Page 370
   9.5.3 Nesting binary modules in script modules......Page 372
  9.6 Summary......Page 375
 10 Module manifests and metadata......Page 376
  10.1 Module folder structure......Page 377
  10.2 Module manifest structure......Page 378
  10.3 Production manifest elements......Page 381
   10.3.2 Runtime dependencies......Page 383
  10.4 Construction manifest elements......Page 385
   10.4.1 The loader manifest elements......Page 386
   10.4.2 Module component load order......Page 389
  10.5 Content manifest elements......Page 390
  10.6 Language restrictions in a manifest......Page 391
   10.7.1 The PSModuleInfo object......Page 393
   10.7.2 Using the PSModuleInfo methods......Page 397
   10.7.3 The defining module versus the calling module......Page 399
   10.7.5 Controlling when modules can be unloaded......Page 403
   10.7.6 Running an action when a module is removed......Page 404
  10.8 Summary......Page 405
 11 Metaprogramming with scriptblocks and dynamic code......Page 407
  11.1 Scriptblock basics......Page 408
   11.1.1 Invoking commands......Page 409
   11.1.2 The scriptblock literal......Page 412
   11.1.3 Defining functions at runtime......Page 413
   11.2.1 Looking at members......Page 415
   11.2.2 Using Add-Member to extend objects......Page 417
   11.2.3 Adding note properties with New-Object......Page 424
  11.3 Using the Select-Object cmdlet......Page 425
   11.4.1 Dynamic script modules......Page 427
   11.4.2 Closures in PowerShell......Page 429
   11.4.3 Creating custom objects from modules......Page 432
   11.5.1 How steppable pipelines work......Page 433
   11.5.2 Creating a proxy command with steppable pipelines......Page 435
  11.6 A closer look at the type-system plumbing......Page 438
   11.6.1 Adding a property......Page 440
   11.6.2 Shadowing an existing property......Page 442
   11.7.2 Adding a CustomClass keyword to PowerShell......Page 443
   11.7.3 Type extension......Page 448
   11.8.1 The Invoke-Expression cmdlet......Page 451
   11.8.3 The ExpandString() method......Page 452
   11.8.5 Mechanisms for creating scriptblocks......Page 453
   11.8.6 Creating functions using the function: drive......Page 454
   11.9.1 Defining a new .NET class: C#......Page 455
   11.9.2 Defining a new enum at runtime......Page 457
   11.9.3 Dynamic binary modules......Page 458
  11.10 Summary......Page 460
 12 Remoting and background jobs......Page 462
   12.1.1 Commands with built-in remoting......Page 463
   12.1.2 The PowerShell remoting subsystem......Page 464
   12.1.3 Enabling remoting......Page 465
   12.1.4 Additional setup steps for workgroup environments......Page 466
   12.1.5 Enabling remoting in the enterprise......Page 467
   12.2.1 Basic remoting examples......Page 469
   12.2.2 Adding concurrency to the examples......Page 470
   12.2.3 Solving a real problem: multimachine monitoring......Page 472
  12.3 Sessions and persistent connections......Page 477
   12.3.1 Additional session attributes......Page 481
   12.3.2 Using the New-PSSession cmdlet......Page 483
   12.3.3 Interactive sessions......Page 484
   12.3.4 Managing PowerShell sessions......Page 487
  12.4 Implicit remoting......Page 488
   12.4.1 Using implicit remoting......Page 489
   12.4.2 How implicit remoting works......Page 491
  12.5 Background jobs in PowerShell......Page 496
   12.5.2 Working with the job cmdlets......Page 498
   12.5.3 Working with multiple jobs......Page 502
   12.5.4 Starting jobs on remote computers......Page 504
   12.5.5 Running jobs in existing sessions......Page 507
  12.6 Considerations when running commands remotely......Page 508
   12.6.2 Profiles and remoting......Page 509
   12.6.3 Issues running executables remotely......Page 510
   12.6.4 Reading and writing to the console......Page 511
   12.6.5 Remote output vs. local output......Page 512
   12.6.6 Processor architecture issues......Page 513
  12.7 Summary......Page 515
 13 Remoting: configuring applications and services......Page 517
   13.1.1 The PowerShell remoting protocol stack......Page 518
   13.1.2 Using the WSMan cmdlets and providers......Page 524
   13.1.3 Authenticating the target computer......Page 526
   13.1.4 Authenticating the connecting user......Page 529
   13.1.5 Addressing the remoting target......Page 533
   13.1.6 Windows version-specific connection issues......Page 535
   13.1.7 Managing resource consumption......Page 537
   13.2.1 Remote service connection patterns......Page 542
   13.2.2 Working with custom configurations......Page 545
   13.2.3 Creating a custom configuration......Page 546
   13.2.4 Access controls and endpoints......Page 548
   13.2.5 Constraining a PowerShell session......Page 550
   13.2.6 Creating a constrained execution environment......Page 558
  13.3 Summary......Page 566
 14 Errors and exceptions......Page 568
  14.1 Error handling......Page 569
   14.1.1 ErrorRecords and the error stream......Page 570
   14.1.2 The $error variable and –ErrorVariable parameter......Page 575
   14.1.3 Determining if a command had an error......Page 579
   14.1.4 Controlling the actions taken on an error......Page 581
  14.2 Dealing with errors that terminate execution......Page 584
   14.2.1 The trap statement......Page 585
   14.2.2 The try/catch/finally statement......Page 590
   14.2.3 The throw statement......Page 593
  14.3 Debugging with the host APIs......Page 595
   14.3.1 Catching errors with strict mode......Page 597
   14.3.2 The Set-StrictMode cmdlet in PowerShell v2......Page 599
   14.3.3 Static analysis of scripts......Page 604
   14.4.1 Starting the transcript......Page 608
   14.4.2 What gets captured in the transcript......Page 610
   14.5.1 The EventLog cmdlets......Page 612
   14.5.2 Examining the PowerShell event log......Page 618
  14.6 Summary......Page 620
 15 The PowerShell ISE and debugger......Page 621
   15.1.1 Controlling the ISE pane layout......Page 622
   15.1.2 Using the ISE editor......Page 625
   15.1.3 Executing commands in the ISE......Page 629
   15.1.4 Considerations when running scripts in the ISE......Page 631
  15.2 Using multiple PowerShell tabs......Page 633
   15.2.2 Remote session tabs in PowerShell ISE......Page 634
   15.3.1 The $psISE variable......Page 637
   15.3.2 Using the Options property......Page 639
   15.3.3 Managing tabs and files......Page 640
   15.3.4 Working with text panes......Page 644
   15.3.5 Adding a custom menu......Page 648
   15.4.1 The Set-PSDebug cmdlet......Page 653
   15.4.2 Nested prompts and the Suspend operation......Page 658
  15.5 The PowerShell v2 debugger......Page 662
   15.5.1 The graphical debugger......Page 663
  15.6 Command-line debugging......Page 667
   15.6.1 Working with breakpoint objects......Page 668
   15.6.2 Setting breakpoints on commands......Page 671
   15.6.3 Setting breakpoints on variable assignment......Page 672
   15.6.4 Debugger limitations and issues......Page 673
  15.7 Summary......Page 674
PART 2 Using PowerShell......Page 676
 16 Working with files, text, and XML......Page 677
   16.1.1 Providers and the core cmdlets......Page 678
   16.1.2 Working with PSDrives......Page 679
   16.1.3 Working with paths that contain wildcards......Page 681
   16.1.4 Suppressing wildcard processing in paths......Page 682
   16.1.5 The -LiteralPath parameter......Page 684
   16.1.6 The Registry provider......Page 685
  16.2 File processing......Page 686
   16.2.1 Reading and writing files......Page 688
   16.2.2 Writing files......Page 693
   16.2.4 Performance caveats with Get-Content......Page 694
   16.3.1 Using System.String to work with text......Page 695
   16.3.2 Using hashtables to count unique words......Page 698
   16.3.3 Using regular expressions to manipulate text......Page 700
   16.3.4 Searching files with the Select-String cmdlet......Page 702
   16.4.1 Using XML as objects......Page 707
   16.4.2 Adding elements to an XML object......Page 709
   16.4.3 Loading and saving XML files......Page 711
   16.4.4 Processing XML documents in a pipeline......Page 715
   16.4.5 Processing XML with XPath......Page 716
   16.4.6 A hint of XLinq......Page 723
   16.4.7 Rendering objects as XML......Page 725
  16.5 Summary......Page 731
 17 Extending your reach with .NET......Page 733
   17.1.1 .NET basics......Page 734
   17.1.2 Working with assemblies......Page 735
   17.1.3 Finding types......Page 739
   17.1.4 Creating instances of types......Page 741
   17.1.5 Defining new types with Add-Type......Page 743
   17.1.6 Working with generic types......Page 753
   17.2.1 Retrieving a web page......Page 754
   17.2.2 Processing an RSS feed......Page 756
  17.3 PowerShell and graphical user interfaces......Page 757
   17.3.1 PowerShell and WinForms......Page 758
   17.3.2 Creating a winforms module......Page 764
   17.3.3 PowerShell and Windows Presentation Foundation......Page 767
  17.4 Summary......Page 773
 18 Working with COM......Page 774
   18.1.1 Creating COM objects......Page 775
   18.1.2 Identifying and locating COM classes......Page 776
  18.2 Automating Windows with COM......Page 778
   18.2.1 Exploring with the Shell.Application class......Page 779
   18.2.2 Managing browser windows using COM......Page 781
   18.2.3 A browser window management module......Page 784
  18.3 Working with the WScript.Shell class......Page 791
   18.4.1 Looking up a word using Internet Explorer......Page 793
   18.4.2 Using Microsoft Word to do spell checking......Page 795
  18.5 The WSH ScriptControl class......Page 797
   18.5.1 Embedding VBScript code in a PowerShell script......Page 798
   18.5.2 Embedding JScript code in a PowerShell script......Page 799
   18.6.1 Getting started with the Schedule.Service class......Page 800
   18.6.2 Listing running tasks......Page 801
   18.6.3 Creating a new scheduled task......Page 802
   18.6.4 Credentials and scheduled tasks......Page 803
   18.6.5 Viewing the life cycle of a task......Page 806
   18.7.3 Interop assemblies, wrappers, and typelibs......Page 807
  18.8 Summary......Page 809
 19 Management objects: WMI and WS-MAN......Page 811
   19.1.1 Exploring WMI......Page 812
   19.1.2 The WMI infrastructure......Page 813
  19.2 The WMI cmdlets......Page 815
   19.2.1 The WMI cmdlet common parameters......Page 816
   19.2.2 The Get-WmiObject cmdlet......Page 818
   19.2.3 The Set-WmiInstance cmdlet......Page 827
   19.2.4 The Invoke-WmiMethod cmdlet......Page 833
   19.2.5 The Remove-WmiObject cmdlet......Page 836
  19.3 The WMI object adapter......Page 838
   19.3.1 The WMI type accelerators......Page 839
   19.3.2 Putting modified WMI objects back......Page 842
  19.4 Exploring WS-Man......Page 844
   19.4.1 The WS-Man cmdlets......Page 845
   19.4.2 Using Get-WSManInstance to retrieve management data......Page 846
   19.4.3 Updating resources using Set-WSManInstance......Page 854
   19.4.4 Invoking methods with Invoke-WSManAction......Page 855
  19.5 Summary......Page 859
 20 Responding in real time with eventing......Page 861
  20.1 Foundations of event handling......Page 862
  20.2 Synchronous events......Page 863
   20.2.2 Delegates and delegation......Page 864
  20.3 Asynchronous events......Page 867
   20.3.2 The eventing cmdlets......Page 868
  20.4 Working with asynchronous .NET events......Page 869
   20.4.1 Writing a timer event handler......Page 870
   20.4.2 Managing event subscriptions......Page 873
   20.5.1 Automatic variables in the event handler......Page 874
   20.5.2 Dynamic modules and event handler state......Page 876
  20.6 Queued events and the Wait-Event cmdlet......Page 877
   20.7.1 WMI event basics......Page 880
   20.7.2 Class-based WMI event registration......Page 881
   20.7.3 Query-based WMI event registrations......Page 885
   20.8.1 Predefined engine events......Page 889
   20.8.2 Generating events in functions and scripts......Page 890
  20.9 Remoting and event forwarding......Page 891
   20.9.1 Handling remote EventLog events......Page 893
   20.9.2 Serialization issues with remote events......Page 894
  20.10 How eventing works......Page 896
  20.11 Summary......Page 899
 21 Security, security, security......Page 902
   21.1.1 What security is and what it isn’t......Page 903
   21.1.2 Security: perception and reality......Page 904
   21.2.1 Introduction to threat modeling......Page 905
   21.2.2 Classifying threats using the STRIDE model......Page 906
   21.2.3 Security basics: threats, assets, and mitigations......Page 907
   21.3.1 Secure by default......Page 911
   21.3.2 Enabling scripting with execution policy......Page 912
   21.4.1 How public key encryption and one-way hashing work......Page 918
   21.4.3 Self-signed certificates......Page 919
   21.4.4 Using a certificate to sign a script......Page 923
   21.4.5 Enabling strong private key protection......Page 927
   21.4.6 Using the PFX file to sign a file......Page 929
  21.6 Using the SecureString class......Page 930
   21.6.1 Creating a SecureString object......Page 931
   21.6.2 The SecureString cmdlets......Page 932
   21.6.3 Working with credentials......Page 933
   21.6.4 Avoiding Invoke-Expression......Page 937
  21.7 Summary......Page 940
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