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diff --git a/powershell.html.markdown b/powershell.html.markdown new file mode 100644 index 00000000..ce9cfa72 --- /dev/null +++ b/powershell.html.markdown @@ -0,0 +1,321 @@ +--- +category: tool +tool: powershell +contributors: + - ["Wouter Van Schandevijl", "https://github.com/laoujin"] +filename: LearnPowershell.ps1 +--- + +PowerShell is the Windows scripting language and configuration management +framework from Microsoft built on the .NET Framework. Windows 7 and up ship +with PowerShell. +Nearly all examples below can be a part of a shell script or executed directly +in the shell. + +A key difference with Bash is that it is mostly objects that you manipulate +rather than plain text. + +[Read more here.](https://technet.microsoft.com/en-us/library/bb978526.aspx) + +If you are uncertain about your environment: +```powershell +Get-ExecutionPolicy -List +Set-ExecutionPolicy AllSigned +# Execution policies include: +# - Restricted: Scripts won't run. +# - RemoteSigned: Downloaded scripts run only if signed by a trusted publisher. +# - AllSigned: Scripts need to be signed by a trusted publisher. +# - Unrestricted: Run all scripts. +help about_Execution_Policies # for more info + +# Current PowerShell version: +$PSVersionTable +``` + +Getting help: +```powershell +# Find commands +Get-Command about_* # alias: gcm +Get-Command -Verb Add +Get-Alias ps +Get-Alias -Definition Get-Process + +Get-Help ps | less # alias: help +ps | Get-Member # alias: gm + +Show-Command Get-EventLog # Display GUI to fill in the parameters + +Update-Help # Run as admin +``` + +The tutorial starts here: +```powershell +# As you already figured, comments start with # + +# Simple hello world example: +echo Hello world! +# echo is an alias for Write-Output (=cmdlet) +# Most cmdlets and functions follow the Verb-Noun naming convention + +# Each command starts on a new line, or after a semicolon: +echo 'This is the first line'; echo 'This is the second line' + +# Declaring a variable looks like this: +$aString="Some string" +# Or like this: +$aNumber = 5 -as [double] +$aList = 1,2,3,4,5 +$aString = $aList -join '--' # yes, -split exists also +$aHashtable = @{name1='val1'; name2='val2'} + +# Using variables: +echo $aString +echo "Interpolation: $aString" +echo "`$aString has length of $($aString.Length)" +echo '$aString' +echo @" +This is a Here-String +$aString +"@ +# Note that ' (single quote) won't expand the variables! +# Here-Strings also work with single quote + +# Builtin variables: +# There are some useful builtin variables, like +echo "Booleans: $TRUE and $FALSE" +echo "Empty value: $NULL" +echo "Last program's return value: $?" +echo "Exit code of last run Windows-based program: $LastExitCode" +echo "The last token in the last line received by the session: $$" +echo "The first token: $^" +echo "Script's PID: $PID" +echo "Full path of current script directory: $PSScriptRoot" +echo 'Full path of current script: ' + $MyInvocation.MyCommand.Path +echo "FUll path of current directory: $Pwd" +echo "Bound arguments in a function, script or code block: $PSBoundParameters" +echo "Unbound arguments: $($Args -join ', ')." +# More builtins: `help about_Automatic_Variables` + +# Inline another file (dot operator) +. .\otherScriptName.ps1 + + +### Control Flow +# We have the usual if structure: +if ($Age -is [string]) { + echo 'But.. $Age cannot be a string!' +} elseif ($Age -lt 12 -and $Age -gt 0) { + echo 'Child (Less than 12. Greater than 0)' +} else { + echo 'Adult' +} + +# Switch statements are more powerfull compared to most languages +$val = "20" +switch($val) { + { $_ -eq 42 } { "The answer equals 42"; break } + '20' { "Exactly 20"; break } + { $_ -like 's*' } { "Case insensitive"; break } + { $_ -clike 's*'} { "clike, ceq, cne for case sensitive"; break } + { $_ -notmatch '^.*$'} { "Regex matching. cnotmatch, cnotlike, ..."; break } + { 'x' -contains 'x'} { "FALSE! -contains is for lists!"; break } + default { "Others" } +} + +# The classic for +for($i = 1; $i -le 10; $i++) { + "Loop number $i" +} +# Or shorter +1..10 | % { "Loop number $_" } + +# PowerShell also offers +foreach ($var in 'val1','val2','val3') { echo $var } +# while () {} +# do {} while () +# do {} until () + +# Exception handling +try {} catch {} finally {} +try {} catch [System.NullReferenceException] { + echo $_.Exception | Format-List -Force +} + + +### Providers +# List files and directories in the current directory +ls # or `dir` +cd ~ # goto home + +Get-Alias ls # -> Get-ChildItem +# Uh!? These cmdlets have generic names because unlike other scripting +# languages, PowerShell does not only operate in the current directory. +cd HKCU: # go to the HKEY_CURRENT_USER registry hive + +# Get all providers in your session +Get-PSProvider + + +### Pipeline +# Cmdlets have parameters that control their execution: +Get-ChildItem -Filter *.txt -Name # Get just the name of all txt files +# Only need to type as much of a parameter name until it is no longer ambiguous +ls -fi *.txt -n # -f is not possible because -Force also exists +# Use `Get-Help Get-ChildItem -Full` for a complete overview + +# Results of the previous cmdlet can be passed to the next as input. +# grep cmdlet filters the input with provided patterns. +# `$_` is the current object in the pipeline object. +ls | Where-Object { $_.Name -match 'c' } | Export-CSV export.txt +ls | ? { $_.Name -match 'c' } | ConvertTo-HTML | Out-File export.html + +# If you get confused in the pipeline use `Get-Member` for an overview +# of the available methods and properties of the pipelined objects: +ls | Get-Member +Get-Date | gm + +# ` is the line continuation character. Or end the line with a | +Get-Process | Sort-Object ID -Descending | Select-Object -First 10 Name,ID,VM ` + | Stop-Process -WhatIf + +Get-EventLog Application -After (Get-Date).AddHours(-2) | Format-List + +# Use % as a shorthand for ForEach-Object +(a,b,c) | ForEach-Object ` + -Begin { "Starting"; $counter = 0 } ` + -Process { "Processing $_"; $counter++ } ` + -End { "Finishing: $counter" } + +# Get-Process as a table with three columns +# The third column is the value of the VM property in MB and 2 decimal places +# Computed columns can be written more verbose as: +# `@{name='lbl';expression={$_}` +ps | Format-Table ID,Name,@{n='VM(MB)';e={'{0:n2}' -f ($_.VM / 1MB)}} -autoSize + + +### Functions +# The [string] attribute is optional. +function foo([string]$name) { + echo "Hey $name, have a function" +} + +# Calling your function +foo "Say my name" + +# Functions with named parameters, parameter attributes, parsable documention +<# +.SYNOPSIS +Setup a new website +.DESCRIPTION +Creates everything your new website needs for much win +.PARAMETER siteName +The name for the new website +.EXAMPLE +New-Website -Name FancySite -Po 5000 +New-Website SiteWithDefaultPort +New-Website siteName 2000 # ERROR! Port argument could not be validated +('name1','name2') | New-Website -Verbose +#> +function New-Website() { + [CmdletBinding()] + param ( + [Parameter(ValueFromPipeline=$true, Mandatory=$true)] + [Alias('name')] + [string]$siteName, + [ValidateSet(3000,5000,8000)] + [int]$port = 3000 + ) + BEGIN { Write-Verbose 'Creating new website(s)' } + PROCESS { echo "name: $siteName, port: $port" } + END { Write-Verbose 'Website(s) created' } +} + + +### It's all .NET +# A PS string is in fact a .NET System.String +# All .NET methods and properties are thus available +'string'.ToUpper().Replace('G', 'ggg') +# Or more powershellish +'string'.ToUpper() -replace 'G', 'ggg' + +# Unsure how that .NET method is called again? +'string' | gm + +# Syntax for calling static .NET methods +[System.Reflection.Assembly]::LoadWithPartialName('Microsoft.VisualBasic') + +# Note that .NET functions MUST be called with parentheses +# while PS functions CANNOT be called with parentheses +$writer = New-Object System.IO.StreamWriter($path, $true) +$writer.Write([Environment]::NewLine) +$write.Dispose() + +### IO +# Reading a value from input: +$Name = Read-Host "What's your name?" +echo "Hello, $Name!" +[int]$Age = Read-Host "What's your age?" + +# Test-Path, Split-Path, Join-Path, Resolve-Path +# Get-Content filename # returns a string[] +# Set-Content, Add-Content, Clear-Content +Get-Command ConvertTo-*,ConvertFrom-* + + +### Useful stuff +# Refresh your PATH +$env:PATH = [System.Environment]::GetEnvironmentVariable("Path", "Machine") + + ";" + [System.Environment]::GetEnvironmentVariable("Path", "User") +# Find Python in path +$env:PATH.Split(";") | Where-Object { $_ -like "*python*"} + +# Change working directory without having to remember previous path +Push-Location c:\temp # change working directory to c:\temp +Pop-Location # change back to previous working directory + +# Unblock a directory after download +Get-ChildItem -Recurse | Unblock-File + +# Open Windows Explorer in working directory +ii . + +# Any key to exit +$host.UI.RawUI.ReadKey() +return + +# Create a shortcut +$WshShell = New-Object -comObject WScript.Shell +$Shortcut = $WshShell.CreateShortcut($link) +$Shortcut.TargetPath = $file +$Shortcut.WorkingDirectory = Split-Path $file +$Shortcut.Save() +``` + + +Configuring your shell +```powershell +# $Profile is the full path for your `Microsoft.PowerShell_profile.ps1` +# All code there will be executed when the PS session starts +if (-not (Test-Path $Profile)) { + New-Item -Type file -Path $Profile -Force + notepad $Profile +} +# More info: `help about_profiles` +# For a more usefull shell, be sure to check the project PSReadLine below +``` + +Interesting Projects +* [Channel9](https://channel9.msdn.com/Search?term=powershell%20pipeline#ch9Search&lang-en=en) PowerShell tutorials +* [PSGet](https://github.com/psget/psget) NuGet for PowerShell +* [PSReadLine](https://github.com/lzybkr/PSReadLine/) A bash inspired readline implementation for PowerShell (So good that it now ships with Windows10 by default!) +* [Posh-Git](https://github.com/dahlbyk/posh-git/) Fancy Git Prompt (Recommended!) +* [PSake](https://github.com/psake/psake) Build automation tool +* [Pester](https://github.com/pester/Pester) BDD Testing Framework +* [Jump-Location](https://github.com/tkellogg/Jump-Location) Powershell `cd` that reads your mind +* [PowerShell Community Extensions](http://pscx.codeplex.com/) (Dead) + +Not covered +* WMI: Windows Management Intrumentation (Get-CimInstance) +* Multitasking: Start-Job -scriptBlock {...}, +* Code Signing +* Remoting (Enter-PSSession/Exit-PSSession; Invoke-Command)
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