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

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.