Powershell CLI file watcher (put this in your $profile to use it)

watch.ps1

function Wait-FileChange {
    param(
        [string]$FilePath,
        [string]$Command
    )

    $AbsPath = (Resolve-Path $FilePath).Path
    $IsDir = (Get-Item $AbsPath).PSIsContainer

    if ($IsDir) {
        $Dir = $AbsPath
        $Filter = "*.*"
    } else {
        $Dir = Split-Path $AbsPath -Parent
        $Filter = Split-Path $AbsPath -Leaf
    }

    $Watcher = New-Object IO.FileSystemWatcher $Dir, $Filter -Property @{ 
        IncludeSubdirectories = $true
        EnableRaisingEvents = $true
    }

    $CommandBlock = [Scriptblock]::Create($Command)

    clear
    Invoke-Command -ScriptBlock $CommandBlock

    [string] $sourceId = New-Guid
    try {
        $onChange = Register-ObjectEvent $Watcher -EventName Changed -SourceIdentifier $sourceId

        while ($true) {
            $event = Wait-Event -SourceIdentifier $sourceId

            clear
            Invoke-Command -ScriptBlock $CommandBlock

            Remove-Event -SourceIdentifier $sourceId
        }
    }
    finally {
        Unregister-Event -SourceIdentifier $sourceId
        $Watcher.Dispose()
    }
}
Set-Alias watch Wait-FileChange