Download All Files in a SharePoint Document Library using PowerShell

Requirement: Download all files in document library in SharePoint

Download All Documents in a Library using PowerShell:
Here is the PowerShell to download all files in a document library. 

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

#Function to Download All Files from a SharePoint Folder
Function Download-SPFolder($SPFolderURL, $DownloadPath)
{
    Try {
        #Get the Source SharePoint Folder
        $SPFolder = $web.GetFolder($SPFolderURL)
 
        $DownloadPath = Join-Path $DownloadPath $SPFolder.Name 
        #Ensure the destination local folder exists! 
        If (!(Test-Path -path $DownloadPath))
        {    
            #If it doesn't exists, Create
            $LocalFolder = New-Item $DownloadPath -type directory 
        }
 
        #Loop through each file in the folder and download it to Destination
        ForEach ($File in $SPFolder.Files) 
        {
            #Download the file
            $Data = $File.OpenBinary()
            $FilePath= Join-Path $DownloadPath $File.Name
            [System.IO.File]::WriteAllBytes($FilePath, $data)
            Write-host -f Green "`tDownloaded the File:"$File.ServerRelativeURL         
        }
 
        #Process the Sub Folders & Recursively call the function
        ForEach ($SubFolder in $SPFolder.SubFolders)
        {
            If($SubFolder.Name -ne "Forms") #Leave "Forms" Folder
            {
                #Call the function Recursively
                Download-SPFolder $SubFolder $DownloadPath
            }
        }
    }
    Catch {
        Write-host -f Red "Error Downloading Document Library:" $_.Exception.Message
    }  
}

#Main Function
Function Download-SPDocumentLibrary($SiteURL, $LibraryName, $DownloadPath)
{
    Try {
        #Get the  Web
        $Web = Get-SPWeb $SiteURL

        #Delete any existing files and folders in the download location
        If (Test-Path $DownloadPath) {Get-ChildItem -Path $DownloadPath -Recurse| ForEach-object {Remove-item -Recurse -path $_.FullName }}

        #Get the document Library to Download
        $Library = $Web.Lists[$LibraryName]
        Write-host -f magenta "Downloading Document Library:" $Library.Title

         #Call the function to download the document library
        Download-SPFolder -SPFolderURL $Library.RootFolder.Url -DownloadPath $DownloadPath

        Write-host -f Green "*** Download Completed  ***"
    }
    Catch {
        Write-host -f Red "Error Downloading Document Library:" $_.Exception.Message
    }  
}

#Runtime-Variables
$SiteURL = "https://Intranet.crescent.com/sites/marketing"
$LibraryName ="Shared Documents"
$DownloadPath ="C:\Downloads\SP2010"

#Call the Function to export all document libraries from a site
Download-SPDocumentLibrary $SiteURL $LibraryName $DownloadPath

Download All Document Libraries from a SharePoint Site:
How about downloading all files from all document libraries from a SharePoint site?

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

#Function to Download All Files from a SharePoint Folder
Function Download-SPFolder($SPFolderURL, $LocalFolderPath)
{
    Try {
        #Get the Source SharePoint Folder
        $SPFolder = $global:web.GetFolder($SPFolderURL)
 
        $LocalFolderPath = Join-Path $LocalFolderPath $SPFolder.Name 
        #Ensure the destination local folder exists! 
        If (!(Test-Path -path $LocalFolderPath))
        {    
            #If it doesn't exists, Create
            $LocalFolder = New-Item $LocalFolderPath -type directory 
        }
 
        #Loop through each file in the folder and download it to Destination
        ForEach ($File in $SPFolder.Files) 
        {
            #Download the file
            $Data = $File.OpenBinary()
            $FilePath= Join-Path $LocalFolderPath $File.Name
            [System.IO.File]::WriteAllBytes($FilePath, $data)
            Write-host -f Green "`tDownloaded File:"$File.ServerRelativeURL
        }
 
        #Process the Sub Folders & Recursively call the function
        ForEach ($SubFolder in $SPFolder.SubFolders)
        {
            If($SubFolder.Name -ne "Forms") #Leave "Forms" Folder
            {
                #Call the function Recursively
                Download-SPFolder $SubFolder $LocalFolderPath
            }
        }
    }
    Catch {
        Write-host -f Red "Error Downloading Document Library:" $_.Exception.Message
    }  
}

#Main Function
Function Export-SPLibraries()
{
    Try {
        #Get the Source Web
        $global:Web = Get-SPWeb $global:SourceSiteURL

        #Delete any existing files and folders in the download location
        If (Test-Path $global:LocalFolderPath) {Get-ChildItem -Path $global:LocalFolderPath -Recurse| ForEach-object {Remove-item -Recurse -path $_.FullName }}

        #Array to Skip System Libraries
        $SystemLibraries =@("Pages", "Converted Forms", "Master Page Gallery", "Customized Reports", 
                      "Form Templates", "List Template Gallery", "Theme Gallery", "Reporting Templates", 
                          "Site Collection Documents", "Site Collection Images", "Site Pages", "Solution Gallery", 
                               "Style Library", "Web Part Gallery","Site Assets", "wfpub")

        #Get all document libraries - Exclude Hidden and System Libraries
        $LibraryCollection = $Web.lists | Where-Object  { ($_.BaseType -eq "DocumentLibrary") -and ($_.hidden -eq $false) -and ($SystemLibraries -notcontains $_.Title)}

        #Iterate through each list and export
        ForEach($Library in $LibraryCollection)
        {
            Write-host -f magenta "Downloading Document Library:" $Library.Title

            #Call the function to download the document library
            Download-SPFolder -SPFolderURL $Library.RootFolder.Url -LocalFolderPath $global:LocalFolderPath
        } 

        Write-host "*** Download Completed  ***"
    }
    Catch {
        Write-host -f Red "Error Downloading Document Library:" $_.Exception.Message
    }  
}

#region Runtime-Variables
$Global:SourceSiteURL = "https://SP2010.crescent.com/sites/marketing"
$Global:LocalFolderPath ="C:\Migration\Downloads"
#endregion Runtime-Variables

#Call the Function to download all document libraries from a site
Export-SPLibraries