ForEach-Object使用Powershell從文件中刪除行

Question

我正在放置一個簡單的PowerShell腳本，它將查找/替換各種數量的關鍵字。如果找到關鍵字，則應該用不同的短語替換它們。

這適用於存在關鍵字的行，但腳本正在刪除關鍵字不存在的行;這不是我想要的行爲。

我的期望是它會取代KEYWORDS並保持所有其他東西不變。

腳本：

#*============================================= 
#* Script Name: SQLFILE_find_and_replace.ps1 
#* Created: 12-Jun-2013 
#*============================================= 
#* Purpose: Intended for SQLFILE scripts 
#* generated from a datapump dump file. 
#* 
#* Will find and replace "Create [Keyword]" 
#* with "Create or Replace [Keyword]" within a 
#* specified file. 
#*============================================= 

#Keywords for find/replace to act on; adjust as necessary. 
$KEYWORDS = @("PROCEDURE","PACKAGE","FUNCTION","TYPE","SEQUENCE","VIEW","DATABASE LINK","TRIGGER") 

# Get-FileName from http://blogs.technet.com/b/heyscriptingguy/archive/2009/09/01/hey-scripting-guy-september-1.aspx 
Function Get-FileName($initialDirectory) 
{ 
    [System.Reflection.Assembly]::LoadWithPartialName("System.windows.forms") | 
    Out-Null 

    $OpenFileDialog = New-Object System.Windows.Forms.OpenFileDialog 
    $OpenFileDialog.initialDirectory = $initialDirectory 
    $OpenFileDialog.filter = "All files (*.*)| *.*" 
    $OpenFileDialog.ShowDialog() | Out-Null 
    $OpenFileDialog.filename 
} #end function Get-FileName 

#Ask user for file 
$FILENAMELOC=Get-FileName -initialDirectory "C:\" 


Write-Progress -Activity "Loading file" -status "$FILENAMELOC" -percentComplete 0 

$file = (Get-Content -Path $FILENAMELOC) 
$lines = ($file | Measure-Object) 
$lineprocessed = 0 

$file | 
    ForEach-Object { 
     $lineprocessed = $lineprocessed + 1 
     ForEach ($KEYWORD in $KEYWORDS) { 
      if ($_.indexof("$KEYWORD") -ge 0) { 
       if ($KEYWORD -eq "SEQUENCE" -and $_.indexof("MINVALUE") -ge 0) { 
        $SEQUENCENAME = $_.Substring($_.indexof("$KEYWORD"),$_.indexof("MINVALUE")-$_.indexof("$KEYWORD")-1) 
        $DROP = "DROP "+$SEQUENCENAME +";" 
        $CREATE = "CREATE "+$SEQUENCENAME +";" 
        $SQL = $DROP+"`r`n"+$CREATE 
        $_ -replace "CREATE $KEYWORD", $SQL 
       } 
       else { 
        $_ -replace "CREATE $KEYWORD", "CREATE OR REPLACE $KEYWORD" 
       } 
      } 
     } 
     Write-Progress -Activity "Replacing keywords" -status "Running" -percentComplete ([System.Math]::Round((($lineprocessed/$lines.count)*100),2)) 
    } | 
    Set-Content $FILENAMELOC 

測試文件：

This is a test. 
CREATE PROCEDURE Blah 
CREATE TRIGGER Boblawbla 
CREATE FUNCTION 
This is another test 

Watch me disappear. 

結果：

CREATE OR REPLACE PROCEDURE Blah 
CREATE OR REPLACE TRIGGER Boblawbla 
CREATE OR REPLACE FUNCTION 

這是一個Windows 7箱。

Answer 1

這是您的罪魁禍首：

if ($_.indexof("$KEYWORD") -ge 0) { 
    if ($KEYWORD -eq "SEQUENCE" -and $_.indexof("MINVALUE") -ge 0) { 
    ... 
    $_ -replace "CREATE $KEYWORD", $SQL 
    } else { 
    $_ -replace "CREATE $KEYWORD", "CREATE OR REPLACE $KEYWORD" 
    } 
} 

只有2 $_ -replace ...產生輸出管道重定向到Set-Content。您似乎認爲-replace運算符修改了$_中的內容，並且Write-Host $_將該行回顯到管道中。情況並非如此。 $_ -replace ...取值爲$_，替換它找到的匹配項，並將修改後的字符串寫入STDOUT。 Write-Host將消息寫入控制檯，而不是STDOUT。

添加else分支呼應不包含任何關鍵字的線條和你應該罰款：

if ($_.indexof("$KEYWORD") -ge 0) { 
    if ($KEYWORD -eq "SEQUENCE" -and $_.indexof("MINVALUE") -ge 0) { 
    ... 
    $_ -replace "CREATE $KEYWORD", $SQL 
    } else { 
    $_ -replace "CREATE $KEYWORD", "CREATE OR REPLACE $KEYWORD" 
    } 
} else { 
    $_ 
} 

你讓這樣太複雜了，雖然。像這樣的東西應該足夠了（如果我正確地分析你的代碼）：

(Get-Content $FILENAMELOC) | % { 
    $_ -replace 'CREATE SEQUENCE (\S*)', "DROP `$1;`r`nCREATE `$1" ` 
    -replace 'CREATE (PROCEDURE|PACKAGE|FUNCTION|TYPE|VIEW|DATABASE LINK|TRIGGER)', 'CREATE OR REPLACE $1' 
} | Set-Content $FILENAMELOC