Powershell issue with do while loop - powershell

Question

I've got a simple bit of code that looks for a string in a series of log files.
If it finds the string, it should exit the loop (nested inside another loop as part of a function) with $buildlogsuccess = 'True'
If it can't find the string, it should exit and return $buildlogsuccess = 'False'
The select-string statement itself works, however it looks like there's something wrong with the below code:
$logArr = gci C:\build\Logs | where {($_.name -like 'install*.log') -and (! $_.PSIsContainer)} | select -expand FullName
$count = ($logArr).count
Foreach ($log in $logArr) {
Do {
$count -= 1
$buildlogsuccess = [bool](select-string -path $log -simplematch $buildstring)
If (($buildlogsuccess)) {break}
} while ($count -gt '0')
}
When one of the logs has the string, the loop finishes and should return $buildlogsuccess as 'True'.
If I check $log it shows the file that I know has the string (in this instance C:\build\Logs\Installer1.log).
Strangely, at this point $count shows as having a value of -1?
If I take the string out of that file and run again it also exits and returns the correct variable value (and shows the $log variable as the last file in $logArr as expected), but this time $count shows as -24.
My code is also returning $buildlogsuccess as 'False' when the string is present in one of the log files.
Re-tested [bool](select-string -path $log -simplematch $buildstring) by manually populating $log (with a file that has that string) and $buildstring and get 'True' as expected when using
[bool](select-string -path $log -simplematch $buildstring)
Note: Variables it uses:
$buildstring = "Package
'F:\xxx\Bootstrap\apackage\Installsomething.xml' processed
successfully"
Any help identifying where I've gone wrong would be appreciated.

Answer 1

Your code can be greatly simplified:
$buildlogsuccess = Select-String -SimpleMatch -Quiet $buildstring C:\build\Logs\install*.log
The above assumes that there are no directories that match install*.log; if there's a chance of that, pipe the output of Get-ChildItem -File C:\build\Logs -Filter install*.log to Select-String instead.

Answer 2

Do-while will first do the thing, then check the while statement. You're iterating over n files. It doesn't check the value of $count before it executes that portion.
So let's say the first file does not contain the string you're looking for. It will (correctly) decrement the $count variable to zero, and then it moves on to the next $log in $logArr.
Now for each next file in the folder it will decrement $count, and then exit the loop when it sees that $count is not greater than 0.
I don't know why you're using the do-while loop at all here

Answer 3

Thanks Norsk
I over-complicated for myself.
This worked:
$logArr = gci C:\build\Logs | where {($_.name -like 'install*.log') -and (! $_.PSIsContainer)} | select -expand FullName
$count = ($logArr).count
Foreach ($log in $logArr) {
$buildlogsuccess = [bool](select-string -path $log -simplematch $buildstring)
If ($buildlogsuccess) {break}
}