How to check if file is being used by another process - Powershell

Question

I am trying to find a solution which will check whether a file is being used by another process. I don't want to read the contents of the file, as on a 7GB document, this could take a while. Currently I am using the function mentioned below, which is not ideal as the script takes about 5 - 10 minutes to retrieve a value.

function checkFileStatus($filePath)
{
    write-host (getDateTime) "[ACTION][FILECHECK] Checking if" $filePath "is locked"

    if(Get-Content $filePath  | select -First 1)
    {
        write-host (getDateTime) "[ACTION][FILEAVAILABLE]" $filePath
        return $true
    }
    else
    {
        write-host (getDateTime) "[ACTION][FILELOCKED] $filePath is locked"
        return $false
    }
}

Any help would be greatly appreciated

Answer 1

Created a function which solves the above problem:

 function checkFileStatus($filePath)
    {
        write-host (getDateTime) "[ACTION][FILECHECK] Checking if" $filePath "is locked"
        $fileInfo = New-Object System.IO.FileInfo $filePath

        try 
        {
            $fileStream = $fileInfo.Open( [System.IO.FileMode]::Open, [System.IO.FileAccess]::Read, [System.IO.FileShare]::Read )
            write-host (getDateTime) "[ACTION][FILEAVAILABLE]" $filePath
            return $true
        }
        catch
        {
            write-host (getDateTime) "[ACTION][FILELOCKED] $filePath is locked"
            return $false
        }
    }

Answer 2

The function i use to check whether a file is locked or not :

function IsFileLocked([string]$filePath){
    Rename-Item $filePath $filePath -ErrorVariable errs -ErrorAction SilentlyContinue
    return ($errs.Count -ne 0)
}

Answer 3

function IsFileAccessible( [String] $FullFileName )
{
  [Boolean] $IsAccessible = $false

  try
  {
    Rename-Item $FullFileName $FullFileName -ErrorVariable LockError -ErrorAction Stop
    $IsAccessible = $true
  }
  catch
  {
    $IsAccessible = $false
  }
  return $IsAccessible
}

Answer 4

Check this script on poschcode.org:

filter Test-FileLock {
    if ($args[0]) {$filepath = gi $(Resolve-Path $args[0]) -Force} else {$filepath = gi $_.fullname -Force}
    if ($filepath.psiscontainer) {return}
    $locked = $false
    trap {
        Set-Variable -name locked -value $true -scope 1
        continue
    }
    $inputStream = New-Object system.IO.StreamReader $filepath
    if ($inputStream) {$inputStream.Close()}
    @{$filepath = $locked}
}