” http://superuser.com/questions/290461/powershell-zip-file-synchronously

In a nutshell, the idea behind this is testing the output zip archive to see if the file has been added. If not, sleep for a second and try again. If the filename does not occur in the archive, then we assume the zipping is still occurring.

This seems to work well. Maybe to be even more “sure” we can add one more second for cleanup to occur after the file has been added.”

Our version of the script:

#declare functions here
function new-zipfile {
param ($zipfile)
if (! $zipfile.endswith(‘.zip’)) {$zipfile += ‘.zip’}
set-content $zipfile (“PK” + [char]5 + [char]6 + (“$([char]0)” * 18))
(dir $zipfile).IsReadOnly = $false
}

#define variables here
#some strings and numbers we will need
$ShellApplication = New-Object -com Shell.Application

$thismonthint = get-date -f “MM”
$prevmonthint = (get-date).addmonths(-1).tostring(“MM”)

$thisyearlongint = get-date -f “yyyy”

$thislogdir = ‘E:\weblogs\W3SVC2\’
$thiszipfile = $thislogdir + $thisyearlongint + $prevmonthint + ‘.zip’
$zipexists = test-path $thiszipfile

#start program here
#first pass, check for .zip files of previous months. if exists exit. if not exist, create empty .zip file
if (! $zipexists)
{
echo ‘zip file does not exist, creating zip file’
new-zipfile $thiszipfile
}
else
{
return
}

# move all log files where the month number matches the month number of the .zip file
# Jan = 01, Feb = 02, Mar = 03 etc. etc.
foreach ($file in Get-ChildItem $thislogdir)
{

# exclude the .zip files already in the directory (just in case we get a random month match in their filename)
if (! $file.name.endswith(“.zip”))
{

# if the
if ($file.Name.substring(6,2) -match $prevmonthint)
{
$zipfile = $ShellApplication.NameSpace($thiszipfile)
$zipfile.MoveHere($file.fullname)
while($zipfile.Items().Item($file.name) -Eq $null)
{
start-sleep -seconds 1
}
}
}
}

Must confess I never managed to get it run run properly via the Windows task scheduler though ?!!?? I just used to fire it off on the 1st of each month and let it run :o/