Powershell正则表达式读取多行

Question

我正在尝试使用正则表达式读取文件并匹配多行，但遇到了一些问题。我正在尝试读取的文件如下所示：

I 09/07/20 05:55PM [Backup Set] Starting backup to CrashPlan Central: 122 files (93.30MB) to back up
I 09/07/20 06:00PM [Backup Set] Completed backup to CrashPlan Central in 0h:04m:39s: 147 files (197.90MB) backed up, 5.30MB encrypted and sent @ 323.5Kbps (Effective rate: 2.7Mbps)
I 09/07/20 06:00PM  - Unable to backup 1 file (next attempt within 15 minutes)
I 09/07/20 06:15PM [Backup Set] Starting backup to CrashPlan Central: 27 files (250MB) to back up
I 09/07/20 06:19PM [Backup Set] Completed backup to CrashPlan Central in 0h:04m:03s: 28 files (250MB) backed up, 5MB encrypted and sent @ 302.5Kbps (Effective rate: 4.3Mbps)
I 09/07/20 06:34PM [Backup Set] Starting backup to CrashPlan Central: 18 files (169.30KB) to back up

行似乎以CR LF 结尾。最终，我想找到包含“已完成备份到”的每一行，而不是立即包含“无法备份”的行。但是，即使是最简单的查询，我也遇到了麻烦。

这是我在文本中提取的方式：

PS C:\temp> $rawtext = Get-Content '.\new 1.txt' -raw

PS C:\temp> $rawtext.GetType()

IsPublic IsSerial Name                 BaseType
-------- -------- ----                 --------
True     True     String               System.Object


PS C:\temp> $rawtext | Measure-Object -Line

Lines Words Characters Property
----- ----- ---------- --------
    6                       

以及一些简单的正则表达式查询的结果：

PS C:\temp> Select-String -InputObject $rawtext -pattern '^.*Completed.*$' # returns nothing
PS C:\temp> Select-String -InputObject $rawtext -pattern '(?m)^.*Completed.*$' # returns the entire contents of $rawtext
PS C:\temp> Select-String -InputObject $rawtext -pattern '(?ms)^.*Completed.*$' # also returns the entire contents of $rawtext
PS C:\temp> Select-String -InputObject $rawtext -pattern '(?ms)^.*Completed.*\r\n$' # returns nothing
PS C:\temp> Select-String -InputObject $rawtext -pattern '(?ms)^.*Completed.*\r\n' # returns the entire contents of $rawtext

我希望这些查询中至少有一个会返回包含“已完成”的每一行。但显然 Powershell 并没有像我想象的那样处理多行。任何人都可以阐明如何在 Powershell 中处理多行正则表达式吗？

FWIW，以下命令在 OSX 终端中成功获取了我想要的内容，并且本质上是我想在 PoSH 中复制的内容：

completedBackups=$(sed '/Completed[[:space:]]backup[[:space:]]to/!d;$!N;/\n.*Unable[[:space:]]to[[:space:]]backup[[:space:]]/!P;D' $f)

Answer 1

您可以执行以下操作：

$rawtext = Get-Content '.\new 1.txt' -Raw
$rawtext | Select-String -Pattern '(?m)^.*?Completed backup to.*$(?!\r?\n.*Unable to backup)' -AllMatches |
    Foreach-Object {$_.Matches.Value}

说明：

(?m)是多行模式，允许^和$匹配每一行的开头和结尾。

(?!) 是不消耗任何字符的负前瞻。因此，我们从字符串 $ 的末尾向前看，找不到零个或多个回车符 \r? 和换行符 \n 后跟任何字符 .* （在一行上，因为我们没有使用(?s)) 和unable to backup。

-AllMatches 开关指示命令在第一次成功匹配后保持匹配。

使用-Raw 开关很好，因为它可以让我们轻松查看下一行文本。如果没有-Raw，我们将需要跟踪先前通过管道传输到Select-String 的行。这是可行的，但方法不同。

(?s) 或单行模式在此处使用. 匹配字符时会出现一些问题。 . 将在单行模式下匹配换行符。

由于Select-String 返回MatchInfo 对象，您需要访问对象的Matches 属性的Value 属性以获取实际匹配的行。

Answer 2

为什么不这样做...

# Create the data file
'
I 09/07/20 05:55PM [Backup Set] Starting backup to CrashPlan Central: 122 files (93.30MB) to back up
I 09/07/20 06:00PM [Backup Set] Completed backup to CrashPlan Central in 0h:04m:39s: 147 files (197.90MB) backed up, 5.30MB encrypted and sent @ 323.5Kbps (Effective rate: 2.7Mbps)
I 09/07/20 06:00PM  - Unable to backup 1 file (next attempt within 15 minutes)
I 09/07/20 06:15PM [Backup Set] Starting backup to CrashPlan Central: 27 files (250MB) to back up
I 09/07/20 06:19PM [Backup Set] Completed backup to CrashPlan Central in 0h:04m:03s: 28 files (250MB) backed up, 5MB encrypted and sent @ 302.5Kbps (Effective rate: 4.3Mbps)
I 09/07/20 06:34PM [Backup Set] Starting backup to CrashPlan Central: 18 files (169.30KB) to back up
' | 
Out-File -FilePath 'D:\Temp\BackUpLog.txt'


(Get-Content -Path 'D:\temp\BackUpLog.txt').GetType()
# Results
<#
IsPublic IsSerial Name                                     BaseType                                                                                                
-------- -------- ----                                     --------                                                                                                
True     True     Object[]                                 System.Array  
#>
((Get-Content -Path 'D:\temp\BackUpLog.txt') | 
Measure-Object -Line).Lines
# Results
<#
6
#>


(Get-Content -Path 'D:\temp\BackUpLog.txt' -Raw).GetType()
# Results
<#
IsPublic IsSerial Name                                     BaseType                                                                                                
-------- -------- ----                                     --------                                                                                                
True     True     String                                   System.Object 
#>


((Get-Content -Path 'D:\temp\BackUpLog.txt' -Raw) | 
Measure-Object -Line).Lines
# Results
<#
6
#>

# Use Select-String with pattern and -AllMatches
(Get-Content -Path 'D:\temp\BackUpLog.txt').Split([Environment]::NewLine) | 
Select-String -Pattern 'Completed backup to' -AllMatches
# Use RegEx matches to collect specific strings
(Get-Content -Path 'D:\temp\BackUpLog.txt').Split([Environment]::NewLine) -match 'Completed backup to'
# Results of both are
<#
I 09/07/20 06:00PM [Backup Set] Completed backup to CrashPlan Central in 0h:04m:39s: 147 files (197.90MB) backed up, 5.30MB encrypted and sent @ 323.5Kbps (Effective rate: 2.7Mbps)
I 09/07/20 06:19PM [Backup Set] Completed backup to CrashPlan Central in 0h:04m:03s: 28 files (250MB) backed up, 5MB encrypted and sent @ 302.5Kbps (Effective rate: 4.3Mbps)
#>