How can I replace every occurrence of a String in a file with PowerShell

Question

Using PowerShell  I want to replace all exact occurrences of  MYID  in a given file with MyValue  What is the easiest way to do so

User · Answer

You could try something like this     path    C  testFile txt   word    searchword   replacement    ReplacementText   text   get-content  path   newText    text -replace  word  replacement  newText  gt   path

User · Answer

Credit to  rominator007  I wrapped it into a function  because you may want to use it again   function Replace-AllStringsInFile  SearchString  ReplaceString  FullPathToFile         content    System IO File   ReadAllText   FullPathToFile   Replace   SearchString    ReplaceString        System IO File   WriteAllText   FullPathToFile    content      NOTE  This is NOT case sensitive       See this post  String Replace ignoring case

User · Answer

I prefer using the File-class of  NET and its static methods as seen in the following example    content    System IO File   ReadAllText  c  bla txt   Replace   MYID    MyValue    System IO File   WriteAllText  c  bla txt    content    This has the advantage of working with a single String instead of a String-array as with Get-Content  The methods also take care of the encoding of the file  UTF-8 BOM  etc   without you having to take care most of the time   Also the methods don t mess up the line endings  Unix line endings that might be used  in contrast to an algorithm using Get-Content and piping through to Set-Content   So for me  Fewer things that could break over the years   A little-known thing when using  NET classes is that when you have typed in   System IO File     in the PowerShell window you can press the Tab key to step through the methods there

User · Answer

I found a little known but amazingly cool way to do it from Payette s Windows Powershell in Action   You can reference files like variables  similar to  env path  but you need to add the curly braces     c file txt      c file txt  -replace  oldvalue   newvalue

User · Answer

This worked for me using the current working directory in PowerShell  You need to use the FullName property  or it won t work in PowerShell version 5  I needed to change the target  NET framework version in ALL my CSPROJ files   gci -Recurse -Filter   csproj        get-content       FullName     Replace   lt TargetFramework gt net47 lt  TargetFramework gt      lt TargetFramework gt net462 lt  TargetFramework gt       Set-Content       FullName

User · Answer

Here s a fairly simple one that supports multiline regular expressions  multiple files  using the pipeline   specifying output encoding  etc  Not recommended for very large files due to the ReadAllText method    Update-FileText ps1   requires -version 2   lt    SYNOPSIS Updates text in files using a regular expression    DESCRIPTION Updates text in files using a regular expression    PARAMETER Pattern Specifies the regular expression pattern    PARAMETER Replacement Specifies the regular expression replacement pattern    PARAMETER Path Specifies the path to one or more files  Wildcards are not supported  Each file is read entirely into memory to support multi-line searching and replacing  so performance may be slow for large files    PARAMETER CaseSensitive Specifies case-sensitive matching  The default is to ignore case    PARAMETER SimpleMatch Specifies a simple match rather than a regular expression match  i e   the Pattern parameter specifies a simple string rather than a regular expression     PARAMETER Multiline Changes the meaning of   and   so they match at the beginning and end  respectively  of any line  and not just the beginning and end of the entire file  The default is that   and    respectively  match the beginning and end of the entire file    PARAMETER UnixText Causes   to match only linefeed   n  characters  By default    matches carriage return linefeed   r n    Windows-based text files usually use  r n as line terminators  while Unix-based text files usually use only  n     PARAMETER Overwrite Overwrites a file by creating a temporary file containing all replacements and then replacing the original file with the temporary file  The default is to output but not overwrite    PARAMETER Force Allows overwriting of read-only files  Note that this parameter cannot override security restrictions    PARAMETER Encoding Specifies the encoding for the file when -Overwrite is used  Possible values for this parameter are ASCII  BigEndianUnicode  Unicode  UTF32  UTF7  and UTF8  The default value is ASCII    INPUTS System IO FileInfo    OUTPUTS System String  single-line file  or System String    file with more than one line  without the -Overwrite parameter  or nothing with the -Overwrite parameter    LINK about Regular Expressions   EXAMPLE C   gt  Update-FileText ps1   Ferb  and  Phineas     2 and  1  Story txt  This command replaces the text  Ferb and Phineas  with the text  Phineas and Ferb  in the file Story txt and outputs the content  Note that the pattern and replacement strings are enclosed in single quotes to prevent variable expansion    EXAMPLE C   gt  Update-FileText ps1  Perry   Agent P  Story2 txt -Overwrite  This command replaces the text  Perry  with the text  Agent P  in the file Story2 txt    gt    CmdletBinding SupportsShouldProcess    true ConfirmImpact    quot High quot    param     Parameter Mandatory    true Position   0 ValueFromPipeline    true      String     Path      Parameter Mandatory    true Position   1      String   Pattern      Parameter Mandatory    true Position   2      AllowEmptyString       String   Replacement      Switch   CaseSensitive      Switch   SimpleMatch      Switch   Multiline      Switch   UnixText      Switch   Overwrite      Switch   Force      ValidateSet  quot ASCII quot   quot BigEndianUnicode quot   quot Unicode quot   quot UTF32 quot   quot UTF7 quot   quot UTF8 quot       String   Encoding    quot ASCII quot     begin     function Get-TempName       param         path           do          tempName   Join-Path  path   IO Path   GetRandomFilename              while   Test-Path  tempName        tempName        if    SimpleMatch            Pattern    Regex   Escape  Pattern        else       if   -not  UnixText            Pattern    Pattern -replace     lt           r                function New-Regex        regexOpts    Text RegularExpressions RegexOptions   None     if   -not  CaseSensitive            regexOpts    regexOpts -bor  Text RegularExpressions RegexOptions   IgnoreCase           if    Multiline            regexOpts    regexOpts -bor  Text RegularExpressions RegexOptions   Multiline           New-Object Text RegularExpressions Regex  Pattern  regexOpts         Regex   New-Regex    function Update-FileText       param         path            pathInfo   Resolve-Path -LiteralPath  path     if    pathInfo           if    Get-Item  pathInfo  GetType   FullName -eq  quot System IO FileInfo quot               fullName    pathInfo Path         Write-Verbose  quot Reading   fullName  quot           text    IO File   ReadAllText  fullName          Write-Verbose  quot Finished reading   fullName  quot          if   -not  Overwrite                regex Replace  text  Replacement                    else              tempName   Get-TempName  Split-Path  fullName -Parent            Set-Content  tempName  null -Confirm  false           if                      Write-Verbose  quot Created file   tempName  quot              try                 Write-Verbose  quot Started writing   tempName  quot                 IO File   WriteAllText  quot  tempName quot   Regex Replace  text  Replacement   Text Encoding    Encoding                Write-Verbose  quot Finished writing   tempName  quot                Write-Verbose  quot Started copying   tempName  to   fullName  quot                Copy-Item  tempName  fullName -Force  Force -ErrorAction Continue               if                          Write-Verbose  quot Finished copying   tempName  to   fullName  quot                                Remove-Item  tempName               if                          Write-Verbose  quot Removed file   tempName  quot                                            catch  Management Automation MethodInvocationException                  Write-Error  Error 0                                                    else           Write-Error  quot The item   path  must be a file in the file system  quot  -Category InvalidType                      process     foreach    PathItem in  Path         if    Overwrite           if    PSCmdlet ShouldProcess  quot   PathItem  quot   quot Overwrite file quot               Update-FileText  PathItem                   else         Update-FileText  PathItem              Also available as a gist on Github

User · Answer

If You Need to Replace Strings in Multiple Files   It should be noted that the different methods posted here can be wildly different with regard to the time it takes to complete  For me  I regularly have large numbers of small files  To test what is most performant  I extracted 5 52 GB  5 933 604 999 bytes  of XML in 40 693 separate files and ran through three of the answers I found here      5 52 GB  5 933 604 999 bytes  of XML files  40 693 files         Test 1 - Plain Replace  start   get-date  xmls    Get-ChildItem -Path  I  TestseT All XML  -Recurse -Filter   xml  FullName foreach   xml in  xmls     Get-Content  xml  replace             Set-Content  xml    end     get-date NEW-TIMESPAN    Start  Start    End  End  lt   TotalMinutes  103 725113128333   gt        Test 2 - Replace with -Raw  start   get-date  xmls    Get-ChildItem -Path  I  TestseT All XML  -Recurse -Filter   xml  FullName foreach   xml in  xmls     Get-Content  xml -Raw  replace             Set-Content  xml    end     get-date NEW-TIMESPAN    Start  Start    End  End  lt   TotalMinutes  10 1600227983333   gt        Test 3 -  NET  System IO  start   get-date  xmls    Get-ChildItem -Path  I  TestseT All XML  -Recurse -Filter   xml  FullName foreach   xml in  xmls     txt    System IO File   ReadAllText   xml   Replace            System IO File   WriteAllText   xml    txt     end     get-date NEW-TIMESPAN    Start  Start    End  End  lt   TotalMinutes  5 83619516833333   gt

User · Answer

Get-Content file txt     Foreach-Object     -replace    MYID     MyValue       Out-File file txt   Note the parentheses around  Get-Content file txt  is required      Without the parenthesis the content is read  one line at a time  and flows down the pipeline until it reaches out-file or set-content  which tries to write to the same file  but it s already open by get-content and you get an error  The parenthesis causes the operation of content reading to be performed once  open  read and close   Only then when all lines have been read  they are piped one at a time and when they reach the last command in the pipeline they can be written to the file  It s the same as  content content   content   where

User · Answer

Small correction for the Set-Content command  If the searched string is not found the Set-Content command will blank  empty  the target file   You can first verify if the string you are looking for exist or not  If not it will not replace anything   If  select-string -path  c  Windows System32 drivers etc hosts  -pattern  String to look for           Get-Content c  Windows System32 drivers etc hosts  replace  String to look for    String to replace with     Set-Content c  Windows System32 drivers etc hosts      Else  Nothing happened

User · Answer

A bit old and different  as I needed to change a certain line in all instances of a particular file name  Also  Set-Content was not returning consistent results  so I had to resort to Out-File  Code below    FileName      OldLine       NewLine       Drives   Get-PSDrive -PSProvider FileSystem foreach   Drive in  Drives        Push-Location  Drive Root         Get-ChildItem -Filter  quot  FileName quot  -Recurse   ForEach                 Get-Content    FullName  Replace  OldLine   NewLine    Out-File    FullName               Pop-Location     This is what worked best for me on this PowerShell version   Major Minor Build Revision 5 1 16299 98

User · Answer

Use  V3 version     Get-Content c  temp test txt  replace   MYID     MyValue     Set-Content c  temp test txt   Or for V2    Get-Content c  temp test txt  -replace    MYID      MyValue    Set-Content c  temp test txt

User · Answer

The one above only runs for  One File  only  but you can also run this for multiple files within your folder   Get-ChildItem  C yourfile  xml  -Recurse   ForEach         Get-Content      ForEach       -replace   MYID     MyValue            Set-Content

User · Answer

This is what I use  but it is slow on large text files   get-content  pathToFile          -replace  stringToReplace   replaceWith     set-content  pathToFile   If you are going to be replacing strings in large text files and speed is a concern  look into using System IO StreamReader and System IO StreamWriter   try       reader    System IO StreamReader   pathToFile     data    reader ReadToEnd       reader close     finally      if   reader -ne  null               reader dispose            data    data -replace  stringToReplace   replaceWith  try       writer    System IO StreamWriter   pathToFile     writer write  data      writer close     finally      if   writer -ne  null               writer dispose             The code above has not been tested    There is probably a more elegant way to use StreamReader and StreamWriter for replacing text in a document  but that should give you a good starting point

[powershell] How can I replace every occurrence of a String in a file with PowerShell?

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