Creating a zipped/compressed folder in Windows using Powershell or the command line

Question

I am creating a nightly database schema file and would like to put all the files created each night, one for each database, into a folder and compress that folder. I have a

Answer 1

Used voithos' answer to zip files up in powershell, just had one problem with the Add-Zip function, the Start-sleep -milliseconds 500 caused problems if the file couldn't be fully zipped up in that time -> the next one starting before it was complete caused errors and some files not to be zipped.

So after playing around for a bit, first trying to get a counter going to check the count of the $zipPackage.Items() and only continuing after the items count increased (which did not work as it would return 0 in some cases when it should not) I found that it will return 0 if the package is still zipping/copying the files up (I think, haha). Added a simple while loop with the start-sleep inside of it, waiting for the zipPackage.Items().count to be a non-zero value before continuing and this seems to solve the problem.

function Add-Zip
{
param([string]$zipfilename)

if(-not (test-path($zipfilename)))
{
    set-content $zipfilename ("PK" + [char]5 + [char]6 + ("$([char]0)" * 18))
    (dir $zipfilename).IsReadOnly = $false  
}

$shellApplication = new-object -com shell.application
$zipPackage = $shellApplication.NameSpace($zipfilename)

foreach($file in $input) 
{ 
        $zipPackage.CopyHere($file.FullName)
        do
        {
            Start-sleep -milliseconds 250
        }
        while ($zipPackage.Items().count -eq 0)
}
}

Answer 2

Here's a couple of zip-related functions that don't rely on extensions: Compress Files with Windows PowerShell.

The main function that you'd likely be interested in is:

function Add-Zip
{
    param([string]$zipfilename)

    if(-not (test-path($zipfilename)))
    {
        set-content $zipfilename ("PK" + [char]5 + [char]6 + ("$([char]0)" * 18))
        (dir $zipfilename).IsReadOnly = $false  
    }

    $shellApplication = new-object -com shell.application
    $zipPackage = $shellApplication.NameSpace($zipfilename)

    foreach($file in $input) 
    { 
            $zipPackage.CopyHere($file.FullName)
            Start-sleep -milliseconds 500
    }
}

Usage:

dir c:\demo\files\*.* -Recurse | Add-Zip c:\demo\myzip.zip

There is one caveat: the shell.application object's NameSpace() function fails to open up the zip file for writing if the path isn't absolute. So, if you passed a relative path to Add-Zip, it'll fail with a null error, so the path to the zip file must be absolute.

Or you could just add a $zipfilename = resolve-path $zipfilename at the beginning of the function.

Answer 3

This compresses .\in contents to .\out.zip with System.IO.Packaging.ZipPackage following the example here

$zipArchive = $pwd.path + "\out.zip"
[System.Reflection.Assembly]::Load("WindowsBase,Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35")
$ZipPackage=[System.IO.Packaging.ZipPackage]::Open($zipArchive, [System.IO.FileMode]"OpenOrCreate", [System.IO.FileAccess]"ReadWrite")
$in = gci .\in | select -expand fullName
[array]$files = $in -replace "C:","" -replace "\\","/"
ForEach ($file In $files) {
   $partName=New-Object System.Uri($file, [System.UriKind]"Relative")
   $part=$ZipPackage.CreatePart($partName, "application/zip", [System.IO.Packaging.CompressionOption]"Maximum")
   $bytes=[System.IO.File]::ReadAllBytes($file)
   $stream=$part.GetStream()
   $stream.Write($bytes, 0, $bytes.Length)
   $stream.Close()
                                                    }
$ZipPackage.Close()

Answer 4

As of PowersShell 5 there is a Compress-Archive cmdlet that does the task out of the box.

Answer 5

Using PowerShell Version 3.0:

Copy-ToZip -File ".\blah" -ZipFile ".\blah.zip" -Force

Hope this helps.

Answer 6

A native way with latest .NET 4.5 framework, but entirely feature-less:

Creation:

Add-Type -Assembly "System.IO.Compression.FileSystem" ;
[System.IO.Compression.ZipFile]::CreateFromDirectory("c:\your\directory\to\compress", "yourfile.zip") ;

Extraction:

Add-Type -Assembly "System.IO.Compression.FileSystem" ;
[System.IO.Compression.ZipFile]::ExtractToDirectory("yourfile.zip", "c:\your\destination") ;

As mentioned, totally feature-less, so don't expect an overwrite flag.