powershell - 备份文件删除器

Question

我有一个充满备份文件的目录，但需要自动清理该目录，因为我的空间不足。最简单的方法是使用 powershell 脚本。
备份每天创建 2 个备份。我想每天保留 2 个备份，持续 7 天，超过 7 天但不超过 3 个月的备份我想每天保留 1 个，我想每周保留 1 个超过 3 个月的备份。超过 2 年的所有内容都会被删除。
我编写的第一个函数删除了 2 年以上的所有内容:

$checkPath = "C:\demo\"
$list = (Get-ChildItem -Path $checkPath | Where-Object {$_.LastWriteTime -lt (Get-Date).AddYears(-2)}).FullName
$count = $list.Length
for ($i = 0; $i -lt $count; $i += 1)
{
    Write-Verbose "[$i] $($list[$i])"
    Remove-Item -Path $list[$i] 
}

之后，我创建了一个删除每个第二个备份的函数:

$checkPath = "C:\demo\"
$list = (Get-ChildItem -Path $checkPath | Where-Object {$_.LastWriteTime -lt (Get-Date).AddDays(-7)} | Where-Object {$_.LastWriteTime -lt (Get-Date).AddMonths(-3)}).FullName
$count = $list.Length
for ($i = 0; $i -lt $count; $i += 2)
{
    Write-Verbose "[$i] $($list[$i])"
    Remove-Item -Path $list[$i] 
}

好吧，我觉得有点迷茫，我在这里走对了路吗？有没有人可能有建议做这个“更好”？

Answer 1

同样，除了代码中的内容外，不会做太多细节。希望评论说得足够响亮

$checkPath = 'C:\temp'

$classified = switch ((Get-ChildItem -Path $checkPath -File | Group-Object { $_.LastWriteTime.Date }) ) {
    # Last 7 days
    { [datetime]::Parse(($_.Name)) -ge [datetime]::Today.AddDays(-7) } {
        $keep = $_.group | Sort-Object LastWriteTime | Select-Object -Last 2
        $keep | ForEach-Object {
            [pscustomobject]@{Path = $_.fullname; LastWriteTime = $_.LastWriteTime; Action = 'Keep'; Interval = '<= 7 days' }
        }
        $remove = $_.group | Where-Object { $_ -notin $keep }
        $remove | ForEach-Object {
            [pscustomobject]@{Path = $_.fullname; LastWriteTime = $_.LastWriteTime; Action = 'Remove'; Interval = '<= 7 days' }
        }
    }
    { [datetime]::Parse(($_.Name)) -lt [datetime]::Today.AddDays(-7) -and
        [datetime]::Parse(($_.Name)) -ge [datetime]::Today.AddMonths(-3) } {
        # Between 7 days and 3 months $_.Name -ForegroundColor Green

        $keep = $_.group | Sort-Object LastWriteTime | Select-Object -Last 1
        $keep | ForEach-Object {
            [pscustomobject]@{Path = $_.fullname; LastWriteTime = $_.LastWriteTime; Action = 'Keep'; Interval = 'Between 7 days and 3 months' }
        }
        $remove = $_.group | Where-Object { $_ -notin $keep }
        $remove | ForEach-Object {
            [pscustomobject]@{Path = $_.fullname; LastWriteTime = $_.LastWriteTime; Action = 'Remove'; Interval = 'Between 7 days and 3 months' }
        }
    }
    { [datetime]::Parse(($_.Name)) -lt [datetime]::Today.AddMonths(-3) -and
        [datetime]::Parse(($_.Name)) -ge [datetime]::Today.AddYears(-2) } {
        # Between 3 months and 2 years $_.Name -ForegroundColor Green
        # Set to unknown for now.  Group by weekOfYear later to make determination
        $_.group | ForEach-Object {
            [pscustomobject]@{Path = $_.Fullname; LastWriteTime = $_.LastWriteTime; Action = 'Unknown'; Interval = 'Between 3 months and 2 years' }
        }
    }
    Default {
        $_.group | ForEach-Object {
            # Everything after 2 years $_.Name -ForegroundColor Green
            [pscustomobject]@{Path = $_.fullname; LastWriteTime = $_.LastWriteTime; Action = 'Remove'; Interval = '> 2 years' }
        }
    }
}

# Needed to determine and group by week of year
$cultureInfo = [cultureinfo]::new('en-US')
$calendar = $cultureInfo.Calendar;
$calendarRule = $cultureInfo.DateTimeFormat.CalendarWeekRule
$firstDayOfWeek = $cultureInfo.DateTimeFormat.FirstDayOfWeek


$classified | Where-Object Interval -EQ 'Between 3 months and 2 years' |
    # Group all files between 3 months and 2 years by weekOfYear and Year and set latest one to keep, others to remove
    Group-Object { $calendar.GetWeekOfYear($_.LastWriteTime, $calendarRule, $firstDayOfWeek) }, { $_.LastWriteTime.Year } |
    ForEach-Object {
        $keep = $_.group | Sort-Object LastWriteTime | Select-Object -Last 1
        $keep | ForEach-Object { $_.Action = 'Keep' }

        $remove = $_.group | Where-Object { $_ -notin $keep }
        $remove | ForEach-Object { $_.Action = 'Remove' }
    }

$classified | Sort-Object LastWriteTime | Out-Host

$classified | Where-Object Action -EQ 'Remove' | Remove-Item -WhatIf

输出

Path                                                      LastWriteTime       Action Interval
----                                                      -------------       ------ --------
C:\temp\20210101 - 20210108.pdf                           13.01.2021 09:15:22 Keep   Between 3 months and 2 years
C:\temp\20210115 - 20210122.pdf                           26.01.2021 15:57:47 Keep   Between 3 months and 2 years
C:\temp\rm_50117.pbl                                      14.05.2021 15:26:41 Keep   Between 7 days and 3 months
C:\temp\zipped.zip                                        19.05.2021 18:35:12 Remove Between 7 days and 3 months
C:\temp\zipped2.zip                                       19.05.2021 18:40:54 Remove Between 7 days and 3 months
C:\temp\zipped3.zip                                       19.05.2021 18:46:05 Keep   Between 7 days and 3 months
C:\temp\xxx_Some Doc ID 2333 _other stuff_more stuff.junk 20.05.2021 23:32:43 Keep   Between 7 days and 3 months
C:\temp\testlksj.ps1                                      21.05.2021 22:28:03 Keep   Between 7 days and 3 months
C:\temp\skdljfsdkf.ps1                                    22.05.2021 09:04:29 Remove Between 7 days and 3 months
C:\temp\testparam.ps1                                     22.05.2021 17:08:33 Remove Between 7 days and 3 months
C:\temp\gitignorepath.txt                                 22.05.2021 21:03:06 Keep   Between 7 days and 3 months
C:\temp\lslkdfjl.ps1                                      23.05.2021 00:56:13 Remove Between 7 days and 3 months
C:\temp\test2.txt                                         23.05.2021 10:17:24 Remove Between 7 days and 3 months
C:\temp\test3.txt                                         23.05.2021 10:17:38 Remove Between 7 days and 3 months
C:\temp\test4.txt                                         23.05.2021 10:17:50 Keep   Between 7 days and 3 months
C:\temp\fromVS.txt                                        24.05.2021 22:57:44 Keep   <= 7 days
C:\temp\testlksfsdfsdj.ps1                                25.05.2021 16:55:45 Keep   <= 7 days
C:\temp\dslkfjlds.ps1                                     26.05.2021 23:35:23 Keep   <= 7 days
C:\temp\slkfjdslfj.ps1                                    27.05.2021 00:35:09 Keep   <= 7 days
C:\temp\testgit.log                                       31.05.2021 13:28:19 Keep   <= 7 days
C:\temp\out.log                                           31.05.2021 13:51:37 Keep   <= 7 days

What if: Performing the operation "Remove File" on target "C:\temp\zipped.zip".
What if: Performing the operation "Remove File" on target "C:\temp\zipped2.zip".
What if: Performing the operation "Remove File" on target "C:\temp\skdljfsdkf.ps1".
What if: Performing the operation "Remove File" on target "C:\temp\testparam.ps1".
What if: Performing the operation "Remove File" on target "C:\temp\lslkdfjl.ps1".
What if: Performing the operation "Remove File" on target "C:\temp\test2.txt".
What if: Performing the operation "Remove File" on target "C:\temp\test3.txt".