Replacing all GUIDs in a file with new GUIDs from the command line

Question

I have a file containing a large number of occurrences of the string Guid="GUID HERE" (where GUID HERE is a unique GUID at each occurrence) and I want to replace every existing GUID with a new unique GUID.

This is on a Windows development machine, so I can generate unique GUIDs with uuidgen.exe (which produces a GUID on stdout every time it is run). I have sed and such available (but no awk oddly enough).

I am basically trying to figure out if it is possible (and if so, how) to use the output of a command-line program as the replacement text in a sed substitution expression so that I can make this replacement with a minimum of effort on my part. I don't need to use sed -- if there's another way to do it, such as some crazy vim-fu or some other program, that would work as well -- but I'd prefer solutions that utilize a minimal set of *nix programs since I'm not really on *nix machines.

To be clear, if I have a file like this:

etc etc Guid="A" etc etc Guid="B"

I would like it to become this:

etc etc Guid="C" etc etc Guid="D"

where A, B, C, D are actual GUIDs, of course.

(for example, I have seen xargs used for things similar to this, but it's not available on the machines I need this to run on, either. I could install it if it's really the only way, although I'd rather not)

Answer 1

I rewrote the C# solution in PowerShell. I figured it would be easier for you to run a powershell script then compile a C# exe.

Steps for using this:

1. Download/install powershell
2. Save the code below somewhere, named GuidSwap.ps1
3. Modify the $filename and $outputFilename variables to suit your needs
4. Run powershell -noexit c:\location\to\guidswap.ps1

---

## GuidSwap.ps1
##
## Reads a file, finds any GUIDs in the file, and swaps them for a NewGUID
##

$filename = "d:\test.txt"
$outputFilename = "d:\test_new.txt"

$text = [string]::join([environment]::newline, (get-content -path $filename))

$sbNew = new-object system.text.stringBuilder

$pattern = "[a-fA-F0-9]{8}-([a-fA-F0-9]{4}-){3}[a-fA-F0-9]{12}"

$lastStart = 0
$null = ([regex]::matches($text, $pattern) | %{
    $sbNew.Append($text.Substring($lastStart, $_.Index - $lastStart))
    $guid = [system.guid]::newguid()
    $sbNew.Append($guid)
    $lastStart = $_.Index + $_.Length
})
$null = $sbNew.Append($text.Substring($lastStart))

$sbNew.ToString() | out-file -encoding ASCII $outputFilename

Write-Output "Done"