# Variables
# param defines -sha script argument and sets "" as default value

$args, $args[0] : args passed to script, by position

if ($sha -eq "") {
	$sha = (git rev-parse HEAD) | Out-String
	$sha = $sha.Trim()
}

# Variable expansion
Write-Host "sha: $sha" # writes the value of $sha
Write-Host 'sha: $sha is not expanded' # $sha is literal, not expanded inside ''

• Write-Host
• Out-String
• Get-Variable : list all PowerShell variables
• Get-ChildItem env: : list all env variables
• gci env:PATH : get $PATH
• Get-ChildItem -Recurse -Filter "*.chm" -EA SilentlyContinue | Select Length,Name : find all *.chm files
• wget "http://blog.kowalczyk.info" -OutFile "index.html" : download url to index.html. wget is alias for Invoke-WebRequest
• get-command code : equivalent of which in unix, find full path of vscode executable

# get PowerShell to inherit changes from .bat file:
cmd.exe /k "scripts\vc.bat & powershell"

# $path is dict Name/Value, where Name is "Path" and Value is value of PATH environment variable
$path = gci env:PATH
$dirs = $path.Value.Split(";")
(gci env:Path).Value.Split(";")

$line.Split("{.}")[1] : split $line by "." and get the second part

$env:PATH -split ';' : show components of $PATH

$line -Like "*.xml" : return true if matches regular expression

[IO.Path]::GetExtension($line) : call a function on $line

function isFileOnList($list, $file) {
	foreach ($item in $list) {
		$inList = $item.ToLower().EndsWith($file)
		if ($inList) {
			return $inList
		}
	}
	return False
}

$list = @("foo\bar.cpp", "foo.txt")
$in = isFileOnList($list, ".txt")

gci | Sort-Object Name -Descending : sort list of files by Name in descending order

# execute 'git rev-parse HEAD' and assign to a variable
$sha1 = (git rev-parse HEAD) | Out-String
$sha1 = $sha1.Replace([System.Environment]::NewLine,"")

# single-line comment
<#
multi-line
comment
#>

Set-StrictMode -Version Latest
$ErrorActionPreference = "Stop"
# call exitIfFailed after executing a command
function exitIfFailed { if ($LASTEXITCODE -ne 0) { exit } }

$DATE = [int][double]::Parse((Get-Date -UFormat %s))

See https://github.com/kjk/exp/blob/master/winstrap.ps1