$PSDefaultParameterValues["Get-Process:ID"] = $pid
Get-Process

# generate a list of all cmdlets and aliases (along with their brief synopses)
Get-Help * -Category Cmdlet | Select-Object Name,Synopsis | Format-Table -Auto

#  Converting PowerShell commands into a Base64-encoded form  (54)
$commands = '1..3 | % { "PowerShell Command" }'
$bytes = [System.Text.Encoding]::Unicode.GetBytes($commands)
$encodedString = [Convert]::ToBase64String($bytes)
# Once you have the encoded string, you can use it as the value of the EncodedCommand parameter
# Launching PowerShell with an encoded command from cmd.exe
C:\Temp>PowerShell -EncodedCommand MQAuAC4AMQAwACAAfAAgACUAIAB7ACAAIgBQAG8A
dwBlAHIAUwBoAGUAbABsACAAUgBvAGMAawBzACIAIAB9AA==

Get-Process | Where-Object { $_.Name -like "*Search*" }
Get-Process | Where-Object { -not $_.Responding }
Get-Service | Where-Object { $_.Status -eq "Stopped" }
Get-Process | Where-Object Name -like "*Search*"

 
$temperature = 25
if ($temperature -le 0) {"Freezing"}
elseif ($temperature -le 10) { "Cold" }
else {"Hot"}
$result = if (Get-Process -Name notepad) { "Running" } else { "Not running" }
$temperature = 20
switch ($temperature)
{ { $_ -lt 32 } { "Below Freezing"; break }
               32    { "Exactly Freezing"; break }
   { $_ -le 70} { "Warm"; break }
default           { "Hot" } }
for ($counter = 1; $counter -le 10; $counter++) { "Loop number $counter" }
foreach ($file in dir) { "File length: " + $file.Length }
1..10 | foreach { "Working" }
Get-ChildItem | Foreach-Object { "File length: " + $_.Length }
while ($response -ne "QUIT") { $response = Read-Host "Type something" }
do { $response = Read-Host "Type something" } while ($response -ne "QUIT")
do { $response = Read-Host "Type something" } until ($response -eq "QUIT")
"a","b","c" | Foreach-Object `
-Begin { "Starting"; $counter = 0 } `
-Process { "Processing $_"; $counter++ } `
-End { "Finishing: $counter" }

#To pause until the user presses the Enter key, use the pause command :
pause
# To pause until the user presses any key, use the ReadKey() method on the $host object:
$host.UI.RawUI.ReadKey()
# To pause a script for a given amount of time, use the Start-Sleep cmdlet: Start-Sleep 5
Start-Sleep -Milliseconds 300

$myString = 'hello `t $ENV:SystemRoot'
$myString = "hello `t $ENV:SystemRoot"
"Hello ""There""!" #result is: Hello "There"!
'Hello ''There''!' #result is: Hello 'There'!
$version = "Current PowerShell version is: $($PSVersionTable.PSVersion.Major)"
# Here strings may be of either the literal (single-quoted) or expanding (double-quoted) variety
$myHereString = @"
This text may span multiple lines, and may
contain "quotes."
"@
$header = "Report for Today"
$myString = "$header`n$('-' * $header.Length)" #make a line of dashes $header.Length long
# same result but using formatting operator which uses same rules as .NET string formatting
$myString = "{0}`n{1}" -f $header,('-' * $header.Length)
$formatString = "{0,8:D4} {1:C}`n"
$formatString -f 50,2.5677
# 1st number ({0}) is right-aligned qty in a box of eight characters (,8). It is formatted as a decimal number with four digits (:D4).
# 2nd number ({1}) represents the price, which formatted as currency (:C).
"$number2 divided by $number1 is " + $number2 / $number1
"{0} divided by {1} is {2}" -f $number2, $number1, ($number2 / $number1)

"Hello World".Replace("World", "PowerShell")  >> Hello PowerShell
"Hello World" -replace '(.*) (.*)','$2 $1'  >> World Hello
"Power[Shell]" -replace "[Shell]","ful"  >> Powfulr[fulfulfulfulful]
# In regular expressions, square brackets around a set of characters means “match any of the characters inside of the square brackets.” In our example, this translates to “Replace the characters S, h, e, and l with ‘ful’.”
"Power[Shell]" -replace "\[Shell\]","ful"  >> Powerful
"Power[Shell]" -replace ([Regex]::Escape("[Shell]")),"ful"  >> Powerful
# Capitalize the first character (\w) after a word boundary (\b)
[Regex]::Replace("hello world", '\b(\w)', { $args[0].Value.ToUpper() })  >> Hello World
"a.b.c" -split '.',0,"SimpleMatch"   PS > "1234567890" -split { ($_ % 2) -eq 0 }
("A","B","C") -join "`r`n"
Use-Culture en-GB { "quit".ToUpper() } # localisation language
#generate source code or other repetitive text
$process.PsObject.Properties | % { 'Console.WriteLine("{0}: " + process.{0});' -f $_.Name }

[math] | Get-Member -Static # -MemberType method
0..7 | % {write-host $_ ([math]::pow(2,$_)) }
function Convert-RadiansToDegrees($angle) { $angle / (2 * [Math]::Pi) * 360 }
function Convert-DegreesToRadians($angle) { $angle / 360 * (2 * [Math]::Pi) }
[BigInt] "9628546546..." #otherwise PowerShell will truncate to 9.628E+38 
[System.Numerics.Complex]::ImaginaryOne * [System.Numerics.Complex]::ImaginaryOne | fl
Get-ChildItem | Measure-Object -Property Length -Max -Min -Average -Sum
$times = dir | Foreach-Object { $_.LastWriteTime } ## Measure the average Ticks property of those LastWriteTime
$results = $times | Measure-Object Ticks -Average ## Create a new DateTime out of the average Ticks
New-Object DateTime $results.Average  ## Sunday, June 11, 2006 6:45:01 AM
$hexNumber = 0x1234 #prefix hexadeximal numbers with 0x
[Convert]::ToString(1234, 2) #or convert from binary [Convert]::ToInt32("10011010010", 2)
[Convert]::ToString(1234, 16) # or use formatting operator "{0:X4}" -f 1234
# Enumerations
[Enum]::GetNames([System.IO.FileAttributes])
[enum]::GetNames([ConsoleColor]) | % { $num = [ConsoleColor]::$_.Value__; Write-Host "$num - $_" -ForegroundColor $num }

$myArray = 1,2,"Hello World" # specific size $myArray = New-Object string[] 10
$list = New-Object Collections.Generic.List[Int] # $list.Add(10) specific type strongly typed collection 
# frequently modified array - create ArrayList
$myArray = New-Object System.Collections.ArrayList
# cast [void] to supress sending data to output pipeline
[void] $myArray.Add("Hello") # $myArray.RemoveAt(1)
[void] $myArray.AddRange( ("World","How","Are","You") )
$myArray = @(Get-Process Explorer) # treat command output as a list
$myArray = 1,2,"Hello World" # $myArray[1..2 + 0] << array ranges & slicing
# different ways to visit each array element $myArray = 1,2,3
$myArray | Foreach-Object { $sum += $_ }
foreach($element in $myArray) { $sum += $element }
for($counter = 0; $counter -lt $myArray.Count; $counter++) {$sum += $myArray[$counter]}
Get-ChildItem | Sort-Object -Descending Length | Select Name,Length
"Hello","World","And","PowerShell" | Sort-Object { $_.Substring(1,1) }
$list = "Hello","World","And","PowerShell"; $list = $list | Sort-Object; [Array]::Sort($list)
$myHashtable = @{ Key1 = "Value1"; "Key 2" = 1,2,3 }; $myHashtable["New Item"] = 5
$myHashtable = @{}; $myHashtable["Hello"] = "World"; $myHashtable.AnotherHello = "AnotherWorld"
# sort unordered hashtable/list
$myHashtable.GetEnumerator() | Sort Name # or value $myHashtable.GetEnumerator() | Sort Value
$myHashtable = [Ordered] @{Duck = 1;Ali = 2;Hectic = 11;Alien = 4;} #retains order in which added items

$date = Get-Date; $date.DayOfWeek
Measure-Command { Start-Sleep -Milliseconds 337 }; Get-Random -Minimum 1 -Maximum 21
$suits = "Hearts","Clubs","Spades","Diamonds"
$faces = (2..10)+"A","J","Q","K"
$cards = foreach($suit in $suits) {foreach($face in $faces) { "$face of $suit" } }
$cards | Get-Random # A of Spades, 2 of Clubs, ... etc.
1..10 | % { (New-Object System.Random).Next(1, 21) } # OR 1..10 | & { Get-Random -Min 1 -Max 21 }

# 3 ways to read text file
$content = Get-Content c:\temp\file.txt
$content = ${c:\temp\file.txt} # get-content variable syntax
$content = Get-Content c:\temp\file.txt -Raw
$contentLines = [System.IO.File]::ReadAllLines("c:\temp\file.txt")
# If you want split the content based on a string rather than default newlines), use the Get-Content cmdlet’s -Delimiter parameter
Select-String -Simple SearchText file.txt # or Select-String "\(...\) ...-...." phone.txt
Get-ChildItem *.txt -Recurse | Select-String pattern #or dir *.txt -rec | sls pattern 
$matches = Select-String "output file" transcript.txt; $matches | Select LineNumber,Line
Select-String "\(...\) ...-...." phone.txt | Select -Expand Matches
Select-String "\((...)\) ...-...." phone.txt | Select -Expand Matches | Foreach { $_.Groups[1] }
Get-ChildItem | Where { $_ | Select-String "Debug" -Quiet }
# parsing log files
$records = gc AddressBook.txt -Delimiter "----"
$parseExpression = "(?s)Name: (\S*).*Phone: (\S*).*"
$records | Convert-TextObject -ParseExpression $parseExpression
$filename = [System.IO.Path]::GetTempFileName()
$newname = [System.IO.Path]::ChangeExtension($filename, ".cs")
Move-Item $filename $newname # optionally rename temp file
# (... use the file ...) create temp file managed by .NET Framework
Remove-Item -Force $filename
$filename = "file.txt" #replace text in file
$match = "source text"; $replacement = "replacement text"
$content = Get-Content $filename
$content = $content -creplace $match,$replacement
$content -replace '(.*) (.*)','$2, $1' # swapping two strings using RegEx (Regular Expression)
$content | Set-Content $filename