防止在 Powershell 脚本中多次写入输出

Question

我正在尝试输出 $message 以防文件夹中的一个或多个文件与今天或昨天的日期匹配。在这种情况下，如果文件与日期匹配，它应该为每个文件输出一条消息，例如，“file $filename matches”，其中 $filename 是与日期匹配的文件的名称。

另一方面，如果文件与当前日期或昨天的日期不匹配，它也会 return 一条消息，但只有一条消息的文件名与日期不匹配。

以下代码不会发生这种情况：

    $in = $false
    foreach ($file in Get-ChildItem -Path $Directory) {
        $today = $file.LastWriteTime.Date -eq [datetime]::Today
        $yesterday = $file.LastWriteTime.Date -eq [datetime]::Today.AddDays(-1)
        
        if ($today -or $yesterday) {
            $message = "file exists"
            $in = $true
            Write-Output $message
        }
    }
    

    if ($in -eq $false) {
        $message_error = "file does not exist" 
        Write-Output $message_error
    }

相反，当文件与日期（昨天或今天的日期）匹配时，它会多次输出消息，如果像上面那样缩进则超过 20 倍。

至于如果不匹配的话，只输出1x，但应该是2x，因为有2个文件不匹配。

有人可以给我提示吗？

输出应该类似于

如果文件夹中的一个或多个文件匹配日期：

"File example.txt matches date
and
File example2.txt matches date"

否则，如果文件夹中的文件与日期不匹配：

"File example.txt, example2.txt don't match dates"

编辑

相反，我是这样尝试的：

 $in = $false
 foreach ($file in Get-ChildItem -Path $Directory) {
    $today = $file.LastWriteTime.Date -eq [datetime]::Today
    $yesterday = $file.LastWriteTime.Date -eq [datetime]::Today.AddDays(-1)
                
    if ($today -or $yesterday) {
        $msg_found = "file" + $file "exists" 
        $in = $true
               
    } else {
        $msg_notfound = "File" + $file + "Not found"
            
    }
      
 Write-Output $msg_notfound
 Write-Output $msg_found

这里消息输出的数量是正确的，但它们在任何情况下都会出现。如果我使用 if 循环，它会解决吗？

Answer 1

继续我的评论...如果您想输出大于或等于昨天日期的文件的名称，您可以通过几种方法来解决这个问题：

Get-ChildItem -Path $Directory | 
    ForEach-Object -Begin {
        $notMatch = [System.Collections.ArrayList]::new()
        $date     = [datetime]::Today.AddDays(-1)
    } -Process {
        if ($_.LastWriteTime -ge $date) {
            Write-Host -Object  "File: [$($_.Name)] - Matches Date"
        }
        else {
            $null = $notMatch.Add($_.Name)
        }
    } -End {
        ($notMatch -join ', ' ) + "don't match dates."
    }

幸运的是，匹配日期是匹配文件的简单解决方案。至于那些不是的，您可以创建一个数组来保存名称的值，直到循环结束以显示由 (", ") 连接的值。

Answer 2

$Directory="T:\temp2"
$in = $false
$message=""
foreach ($file in Get-ChildItem -Path $Directory) {
    $today = $file.LastWriteTime.Date -eq [datetime]::Today
    $yesterday = $file.LastWriteTime.Date -eq [datetime]::Today.AddDays(-1)
    
    if ($today -or $yesterday) {
        $in = $true
        Write-Output ("File " + $file.Name +" matches date")
    } else {
        $message +=(" "+$file.Name+",")
    }
}


if ($in -eq $false) {
    $message_error= ("File" + $message.Substring(0,$message.Length-1) + " don't matches date")
    Write-Output $message_error
}

Answer 3

简单地收集变量中与参考日期不匹配的日期，并将匹配的文件直接写入控制台：

# set the reference date to midnight using .Date
$refDate = [datetime]::Today.AddDays(-1).Date
# loop through the files in the directory and test their LastWriteTime dates
$notMatch = foreach ($file in (Get-ChildItem -Path $Directory -File)) {
    if ($file.LastWriteTime -ge $refDate) { 
        # use Write-Host so this message doesn't end up in variable $notMatch
        Write-Host "File '$($file.Name)' matches the date"
    }
    else {
        # output the filename so it gets collected in variable $notMatch
        $file.Name
    }
}

# now output the list of files that didn't match to the console
if (@($notMatch).Count) {
    $message = "Files that don't match the date:`r`n{0}" -f ($notMatch -join [environment]::NewLine)
    Write-Host $message -ForegroundColor Red
}
else {
    Write-Host "All files matched the date!" -ForegroundColor Green
}

既然你问了，这里有两个替代代码供你选择

1: 将所有内容都抓取到一个数组变量中，稍后拆分出来

# set the reference date to midnight using .Date
$refDate = [datetime]::Today.AddDays(-1).Date
# loop through the files in the directory and test their LastWriteTime dates
$result = foreach ($file in (Get-ChildItem -Path $Directory -File)) {
    [PsCustomObject]@{
        File        = $file.Name
        MatchesDate = ($file.LastWriteTime -ge $refDate)  # --> either $true or $false
    }
}

# you now have a list of every file name found in the directory, together with a boolean
# value teling you if the LastWriteTime matched the $refDate or not.

# split out for console output
$matchedFiles = ($result | Where-Object { $_.MatchesDate }).File -join [environment]::NewLine
Write-Host "Files that were last modified yesterday or today:`r`n{0}" -f $matchedFiles -ForegroundColor Green

$notMatch = ($result | Where-Object {-not $_.MatchesDate }).File -join [environment]::NewLine
Write-Host "Files that were last modified before yesterday:`r`n{0}" -f $notMatch -ForegroundColor Red

2：在两个单独的列表中捕获所有内容

# set the reference date to midnight using .Date
$refDate = [datetime]::Today.AddDays(-1).Date

# create two lists
$matchedFiles = [System.Collections.Generic.List[string]]::new()
$notMatch     = [System.Collections.Generic.List[string]]::new()

# loop through the files in the directory and test their LastWriteTime dates
# we're not outputting anything inside the list, but add to the appropriate list instead
foreach ($file in (Get-ChildItem -Path $Directory -File)) {
    if ($file.LastWriteTime -ge $refDate) { 
        $matchedFiles.Add($file.Name)
    }
    else {
        $notMatch.Add($file.Name)
    }
}

# you now have separate lists of every iles that matched and files that did not match the date criterium

# console output
Write-Host "Files that were last modified yesterday or today:`r`n{0}" -f ($matchedFiles -join [environment]::NewLine) -ForegroundColor Green
Write-Host "Files that were last modified before yesterday:`r`n{0}" -f ($notMatch -join [environment]::NewLine) -ForegroundColor Red

Answer 4

试试这个：

 foreach ($file in Get-ChildItem -Path $Directory) {
    $today = $file.LastWriteTime.Date -eq [datetime]::Today
    $yesterday = $file.LastWriteTime.Date -eq [datetime]::Today.AddDays(-1)
    
    # If file was written to today or yesterday, write $msg_found           
    if ($today -or $yesterday) {
        $msg_found = "File " + $file + " exists"
        Write-Output $msg_found         
    }
    
    # If not, write $msg_notfound 
    else {
        $msg_notfound = "File " + $file + " not found"
        Write-Output $msg_notfound
            
    }
}

如果我理解正确，它同时编写 $msg_found 和 $msg_notfound 变量的原因是因为它们在 If/Else 之外 声明。

将它们保存在 If/Else 中将使其只在 If 或其他.

编辑： 在上面，我删除了 $in 变量，但我不确定您是否需要它。所以我修改了您在编辑之前发布的脚本，以执行与我最初放置的脚本相同的操作，以防您这样做。

我留下评论告诉你我改变了什么，但如果你有任何问题，请告诉我：

$in = $false
foreach ($file in Get-ChildItem -Path $Directory) {
    $today = $file.LastWriteTime.Date -eq [datetime]::Today
    $yesterday = $file.LastWriteTime.Date -eq [datetime]::Today.AddDays(-1)
    
    # If file was made today or yesterday, $in is true, write $message 
    if ($today -or $yesterday) {
        $message = "$File exists"
        $in = $true
        Write-Output $message
    }
    
    # If not, $in is false for this file in the ForEach loop
    else{
        $in = $false
    }
    
    # Moved the second If statement into the ForEach loop 
    # If the If/Else set $in as false for this file, write $message_error
    if ($in -eq $false) {
    $message_error = "$File does not exist" 
    Write-Output $message_error
    }
}

Answer 5

使用 .Where() method combined with the Split 模式替代已经提出的答案：

$directory = '.'
$targetDate = [datetime]::Today.AddDays(-1)

$Match, $noMatch = (Get-ChildItem -Path $directory -File).Where({
    $_.LastWriteTime -ge $targetDate
}, 'Split')

if($Match)
{
    '=' * 60
    [string]::Format(
        '{0} file{1} found with Date greater than or equal to {2}',
        $Match.Count,
        ($null, 's')[[int]$Match.Count -gt 1],
        $targetDate.ToShortDateString()
    )
    '=' * 60
    ''
    $Match.ForEach({
        '- File: {0} with LastWriteTime {1}' -f $_.Name, $_.LastWriteTime
    })
}
else
{
    '=' * 60
    [string]::Format(
        'No files found with Date greater than or equal to {0}',
        $targetDate.ToShortDateString()
    )
    '=' * 60
    $noMatch | Format-Wide Name -AutoSize
}

防止在 Powershell 脚本中多次写入输出

Prevent output from writing multiple times in Powershell script

powershell

foreach