PowerShell – Mass replace text strings for all files in a directory

Sometimes you need to mass replace all the text string for all files in a directory, or at least all files matching some file mask.

Here’s a quick sample that I put together.

As a BizTalk consultant, I deal with data coming in from customers or trading partners. Sometimes, that data needs to be scrubbed. We were doing multiple rounds of testing, and the trading partner was going to put a fix in place in a few days, but in the meantime, I was having to hand edit each and every file manually, before putting the file into BizTalk. I was really getting tired of that process and wrote the script below.

# Fix various issues in the certain EDI files 
$path = "c:\MyPath\"
$files = get-ChildItem $path -filter "850*.edi" 
#$files  #use this to just display all the filenames 
foreach ($file in $files) 
   Write-Host "`n`nfixing file= $($file.Name)"
   $filetext = Get-Content $file.FullName -Raw   
   # The -Raw (line above) option brings all text into a string, without dividing into lines 
   Write-Host "Old Text in file: $($file.Name)" 
   Write-Host $filetext

   #example of regular text 
   $filetextNew = $filetext     -replace "Texas",        "TEXAS"
   #example of changing EDI tags
   $filetextNew = $filetextNew  -replace "\^WACO", "\^DALLAS"
   $filetextNew = $filetextNew  -replace "\^EXCELLENT",   "\^EU"
   $filetextNew = $filetextNew  -replace "\^MODUSE",      "\^MU"
   $filetextNew = $filetextNew  -replace "\^LIGHTUSE",    "\^LU"
   $filetextNew = $filetextNew  -replace "\^HEAVYUSE",    "\^HU"

   Write-Host "NEW:" 
   Write-Host $filetext 
   Set-Content $file.FullName $filetextNew

I was modifying an EDI file, so I wanted to make sure that the string I was modifying started with the caret symbol. So for example, I really wanted to change “^MODUSE” to “^MU”. Since that caret symbol has special meaning in RegEx (Regular Expressions), I had to put the backslash in front of it as an escape character. So I added the first line to change “Texas” to “TEXAS” to show that the backslahs and caret symbol are not needed for normal text replacement.

The one bug I had in the code above was specifying $file.Name instead of $file.FullName. It almost drove me crazy. It seemed to be returning the filename itself, rather than the contents of the file; probably because that file didn’t exist in the current directory in which the PowerShell script itself was running.

In the past, I used to use a utility called “BK-Replace’Em”, which is now called by the more generic name “Replace Text”. You can download a free copy from EcoByte here. It can do the same thing as above, without writing any code. The only thing is you need to be able to download and install it on your server, and I didn’t want to do that on the various servers that I’m currently working on.


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