带文件检查和重命名的单行管道循环(Single line piped loop with File Check and Rename)

带文件检查和重命名的单行管道循环(Single line piped loop with File Check and Rename)

所以我试图重命名一堆MSSQL备份，如下所示：

DBName_backup_2017_12_20_564451321_567987465.bak

类似的东西

DBName.bak

但也有一个安全检查，以确保如果DBName.bak已经采取它会做DBName_1.bak 。 其中1将是一个增量变量，直到有一个有效的未使用的文件名。

我可以用下面的代码来完成它：

Get-ChildItem *_*.bak | % { # Set the new name, replace everything after the first underscore '_' with # '.bak' $newName = &{$_.Name -replace $_.Name.Substring($_.Name.IndexOf("_")), '.bak'} # Check if new name exists for ($cnt = 1; (Test-Path $newName) -eq $true; $cnt++) { # If it already exists add '_' and a number check again until unused # filename is found $newName = &{$newName -replace '.bak', "_$cnt.bak"} } # Rename file to new filename. Uncomment WhatIf for testing. Rename-Item -Path $_ -NewName $newName #-WhatIf }

我现在想要做的，就是把它与管道系在一条线上，但我没有运气。 特别是让循环与Test-Path检查一起运行。 有谁知道我怎么能这样？

So I'm trying to rename a bunch of MSSQL backups that come out like:

DBName_backup_2017_12_20_564451321_567987465.bak

To Something like

DBName.bak

But also have a safety check to ensure that if DBName.bak is already taken it'll do DBName_1.bak. Where 1 will be an incremental variable until there is a valid unused filename.

I was able to do it with the following code:

Get-ChildItem *_*.bak | % { # Set the new name, replace everything after the first underscore '_' with # '.bak' $newName = &{$_.Name -replace $_.Name.Substring($_.Name.IndexOf("_")), '.bak'} # Check if new name exists for ($cnt = 1; (Test-Path $newName) -eq $true; $cnt++) { # If it already exists add '_' and a number check again until unused # filename is found $newName = &{$newName -replace '.bak', "_$cnt.bak"} } # Rename file to new filename. Uncomment WhatIf for testing. Rename-Item -Path $_ -NewName $newName #-WhatIf }

What I'm trying to do now, is to one line it with piping, but am having no luck. Particularly getting the loop to run with the Test-Path check. Does anyone know how I could one like this?

最满意答案

简单：

$cnt = 0; Get-ChildItem *_*.bak | Rename-Item -NewName { ($_.BaseName -replace '_.*', '_') + $script:cnt++ + $_.Extension } -WhatIf

如果您只想（重新）为具有重复数据库名称的文件编号，则不能真正实现单行。 你需要这样的东西：

Get-ChildItem *_*.bak | ForEach-Object { $basename = $_.BaseName -replace '_.*' $newname = $basename + $_.Extension $script:cnt = 1 while (Test-Path $newname) { $newname = $basename + '_' + $script:cnt++ + $_.Extension } Rename-Item -NewName $newname -WhatIf }

但是，在PowerShell中，您可以使用换行符和分号分隔语句，因此您仍然可以将上述所有内容合并到一行中。 喜欢这个：

Get-ChildItem *_*.bak | ForEach-Object {$basename = $_.BaseName -replace '_.*'; $newname = $basename + $_.Extension; $script:cnt = 1; while (Test-Path $newname) {$newname = $basename + '_' + $script:cnt++ + $_.Extension}; Rename-Item -NewName $newname -WhatIf}

不过，我通常不建议这样做，因为它会使代码难以阅读和调试。

无论采用哪种方式，在验证重命名后都可以按照需要进行操作，然后卸下鸡开关。

Simple:

$cnt = 0; Get-ChildItem *_*.bak | Rename-Item -NewName { ($_.BaseName -replace '_.*', '_') + $script:cnt++ + $_.Extension } -WhatIf

If you just want to (re)number files with duplicate database names you can't truly one-line the thing. You need something like this:

Get-ChildItem *_*.bak | ForEach-Object { $basename = $_.BaseName -replace '_.*' $newname = $basename + $_.Extension $script:cnt = 1 while (Test-Path $newname) { $newname = $basename + '_' + $script:cnt++ + $_.Extension } Rename-Item -NewName $newname -WhatIf }

However, in PowerShell you can separate statements with both newlines and semicolons, so you can still merge all of the above into one line. Like this:

Get-ChildItem *_*.bak | ForEach-Object {$basename = $_.BaseName -replace '_.*'; $newname = $basename + $_.Extension; $script:cnt = 1; while (Test-Path $newname) {$newname = $basename + '_' + $script:cnt++ + $_.Extension}; Rename-Item -NewName $newname -WhatIf}

I don't normally recommend doing this, though, because it makes code unnecessarily hard to read and debug.

Either way, remove the the chicken switch after you verified renaming would work as desired.