Unix `touch` in Powershell

Update-File.ps1

Function Update-File
{
    $Usage = "Usage: Update-File [file1 ... fileN]";
    # if no arguments, display an error
    if ($args.Count -eq 0) {
        throw $Usage;
    }
    # see if any arguments match -h[elp] or --h[elp] 
    foreach($file in $args) {
        if ($file -ilike "-h*" -or $file -ilike "--h*") {
            echo $Usage;
            return;
        }
    }

    foreach($file in $args) {
        if(Test-Path -LiteralPath $file)
        {
            # file exists, update last write time to now
            @setProps = @{
                LiteralPath = $file
                Name = 'LastWriteTime'
                Value = (Get-Data)
            }
            Set-ItemProperty @setProps
        }
        else
        {
            # create new file. 
            # don't use `echo $null > $file` because it creates an UTF-16 (LE)
            # and a lot of tools have issues with that
            echo $null | Out-File -Encoding ascii -LiteralPath $file
            # alternative
            # New-Item -Path $file -ItemType File | Out-Null
        }
    }
}
New-Alias -Name touch -Value Update-File

Credit to: https://superuser.com/a/571154

Improved version, with comments and everything: https://www.reddit.com/r/PowerShell/comments/6uxuk2/replicating_the_unix_touch_command/dlwwjwq/