Try-Catch Powershell -如果目录中已经存在日志文件，则跳过归档

Question

我还在学习powershell -如果我在这个论坛上错误地提出了我的问题，我提前道歉。

我的同事帮我编写了一个powershell脚本来帮助归档日志文件。看起来我们已经按预期运行了，但是由于某些原因，我们的try/catch语句不能正常工作。具体来说，我们希望脚本避免将已经存在的文件移动到我们的目录中。我已经比较了这句话在其他脚本的工作，但我还没有能够排除什么问题可能是。

任何想法吗?到目前为止，脚本看起来是这样的:

#----- Script variables 
# variables with static data
$logpath = "C:templog"
$logname = "log-archive-test"
$lognameext = ".log"
# the variables below will be dynamically set later in the script
$Outputstr = ""
$DateVar = ""
$Datestr = ""
$TimeStr = ""
$logTimeStr = ""
$logfiletxt = ""
#-----  Get Date and Time
$FileDate = Get-Date -format yyyy-MM-dd
$Datestr = Get-Date -Format "MM/dd/yyyy"
$TimeStr = Get-Date -Format "HH:mm"

#----- Functions
# Write-File-Host - function to write to a log file and to console
function Write-File-Host 
( [String] $FileHostOutputText,
[String] $FileHostOutputFile
)
{
Process 
{
Write-Output $FileHostOutputText >> $FileHostOutputFile
}
End {Write-Host $FileHostOutputText}
}

#-----------------------------------------  create log destination and filename
$OutputdatafilenameTimeStr = $TimeStr -replace ":", ""
#$Outputdatafilename =  $sqlfile.SubString(0,$i) + " " + $FileDate + "T" + $OutputdatafilenameTimeStr + ".csv"
#$Outputdatatext = $AppOutDataDir + $Outputdatafilename
#$logTimeStr = $TimeStr -replace ":", ""
$logfiletxt = $logpath + $logname + "_" + $FileDate + "T" + $OutputdatafilenameTimeStr + $lognameext

function Format-YearMonth ([datetime]$date) {
# simply output a string like "2021_01"
return '{0:yyyy_MM}' -f $date
}
$sourcePath = 'C:UserstestDesktoplog'
$targetPath = 'C:UserstestDesktoplogArchive'
$thisMonth  = Format-YearMonth (Get-Date)
#--------------------------------------------- Announce starting of Log Archiving
$Datestr = Get-Date -Format "MM/dd/yyyy"
$TimeStr = Get-Date -Format "HH:mm"
$Outputstr = $Datestr + " " + $TimeStr + ": ==================== Starting the Archiving of Log Files"
Write-File-Host $Outputstr $logfiletxt    

Get-ChildItem -Path $sourcePath -File | 
# filter out the files that have a LastWriteTime for this year and month
Where-Object {(Format-YearMonth $_.LastWriteTime) -ne $thisMonth } |
ForEach-Object {
# Set destination Path
$Directory = Join-Path -Path $targetPath -ChildPath (Format-YearMonth $_.LastWriteTime)
# Create directory if it doesn't exsist
#--------------------------------------------- Announce creation of directory if it doesn't exist 
$Datestr = Get-Date -Format "MM/dd/yyyy"
$TimeStr = Get-Date -Format "HH:mm"
$Outputstr = $Datestr + " " + $TimeStr + ": ----------- Create directory $Directory if it doesn't exsist"
Write-File-Host $Outputstr $logfiletxt    
if (!(Test-Path $Directory)) {
$null = New-Item $Directory -type Directory
}
Write-Host "Moving file '$($_.FullName)' to '$Directory'"
# Move File to new location
#--------------------------------------------- Announce moving of files to the Directory
$Datestr = Get-Date -Format "MM/dd/yyyy"
$TimeStr = Get-Date -Format "HH:mm"
$Outputstr = $Datestr + " " + $TimeStr + ": ----------- Moving file '$($_.FullName)' to '$Directory'"
Write-File-Host $Outputstr $logfiletxt    
try {    $_ | Move-Item -Destination $Directory  }

catch {   $Datestr = Get-Date -Format "MM/dd/yyyy"
$TimeStr = Get-Date -Format "HH:mm"
$Outputstr = $Datestr + " " + $TimeStr + ": ----------- File '$($_.FullName)' already exists in '$Directory'"
Write-File-Host $Outputstr $logfiletxt    }
}
#------------------------------------------------- Announce end of Log Archiving
$Datestr = Get-Date -Format "MM/dd/yyyy"
$TimeStr = Get-Date -Format "HH:mm"
$Outputstr = $Datestr + " " + $TimeStr + ": ==================== Archiving completed."
Write-File-Host $Outputstr $logfiletxt  

Answer 1

添加-ErrorAction Stop或-EA Stop到Move-Item。否则，设置为默认的Continue，即Print error to output and generate NO exception。因此，如果没有异常，try块没有什么可捕获的，代码也不会到达catch块。

当-ErrorAction设置为Stop时，生成ActionPreferenceStopException，触发try块异常捕获机制。

或者，您可以使用总是生成异常的本机。net方法[System.IO.File]::Move(...)。

ErrorActionPreference