diff options
| -rw-r--r-- | powershell.html.markdown | 45 |
1 files changed, 40 insertions, 5 deletions
diff --git a/powershell.html.markdown b/powershell.html.markdown index be8311b7..b9f56861 100644 --- a/powershell.html.markdown +++ b/powershell.html.markdown @@ -18,7 +18,7 @@ rather than plain text. After years of evolving, it resembles Python a bit. [Read more here.](https://docs.microsoft.com/powershell/scripting/overview) -Powershell as a Language: +<H3>Powershell as a Language:</H3> ```powershell @@ -116,6 +116,8 @@ $False - 5 # => -5 # (-is vs. -eq) -is checks if two objects are the same type # -eq checks if the objects have the same values. +# Note: we called '[Math]' from .NET previously without the preceeding +# namespaces. We can do the same with [Collections.ArrayList] if preferred [System.Collections.ArrayList]$a = @() # Point a at a new list $a = (1,2,3,4) $b = $a # => Point b at what a is pointing to @@ -541,7 +543,7 @@ True False Guitar Instrument ## 7. Advanced #################################################### -# The powershell pipeline allows us to do things like High-Order Functions +# The powershell pipeline allows things like High-Order Functions # Group Object is a handy command that does incredible things for us # It works much like a GROUP BY in SQL would @@ -554,6 +556,16 @@ True False Guitar Instrument #> Get-Process | Foreach-Object ProcessName | Group-Object +# Useful pipeline examples are iteration and filtering +1..10 | ForEach-Object { "Loop number $PSITEM" } +1..10 | where {$PSITEM -gt 5} | Format-Table + +# A noteable pitfall of the pipeline is it's performance when +# compared with other options +# additionally, raw bytes are not passed through the piipeline +# so passing an image causes some issues +# See more on that in the links at the bottom + <# Asynchronous functions exist in the form of jobs Typically a procedural language @@ -633,7 +645,7 @@ function Format-Range ($start, $end) { Format-Range 2 6 # => 'a','b','g','f','e','d','c','h','i','j','k','l','m','n' ``` -Powershell as a Tool: +<H3>Powershell as a Tool:</H3> Getting Help: @@ -647,7 +659,7 @@ 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 +Show-Command Get-WinEvent # Display GUI to fill in the parameters Update-Help # Run as admin ``` @@ -668,10 +680,32 @@ $PSVersionTable ``` ```Powershell +# Calling external commands, executables, and functions with the call operator. +# the call operator (&) is similar to Invoke-Expression, but IEX runs in current scope. +# Standard usage of '&' would be to invoke a scriptblock inside of your script. +# Notice the variables are scoped +$i = 2 +$scriptblock = { $i=5; Write-Output $i } +& $scriptblock # => 5 +$i # => 2 + +invoke-expression ' $i=5; Write-Output $i ' # => 5 +$i # => 5 + +# Alternatively, to preserve changes to public variables +# you can use "Dot-Sourcing". This will run in the current scope +$x=1 +&{$x=2};$x # => 1 + +. {$x=2};$x # => 2 + + # Remoting into computers is easy Enter-PSSession -ComputerName RemoteComputer + # Once remoted in, you can run commands as if you're local RemoteComputer\PS> Get-Process powershell + <# Handles NPM(K) PM(K) WS(K) CPU(s) Id SI ProcessName ------- ------ ----- ----- ------ -- -- ----------- @@ -727,7 +761,7 @@ foreach ($server in $serverList) { Interesting Projects * [Channel9](https://channel9.msdn.com/Search?term=powershell%20pipeline#ch9Search&lang-en=en) PowerShell tutorials -* [KevinMarquette's Powershell Blog](https://powershellexplained.com/) Really excellent blog that goes into great detail on Powershell +* [KevinMarquette's Powershell Blog](https://powershellexplained.com/) Excellent blog that goes into great detail on Powershell * [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!) @@ -736,3 +770,4 @@ Interesting Projects * [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](https://github.com/Pscx/Pscx) +* [More on the Powershell Pipeline Issue](https://github.com/PowerShell/PowerShell/issues/1908) |