Ian Obermiller

Part time hacker, full time dad.

Replace in files using Powershell and TFS

Posted 2012-07-05

Ever need to find and replace a regex within multiple files using Powershell, and possibly in a TFS workspace? The following function does just that.

It searches the current directory recursively, and if you are in a TFS workspace it will edit the file in TFS before replacing. It also shows a progress bar and has a preview mode that only lists the matching files.

function global:far(
   [Parameter(Mandatory=$true)]$regexFind,
   [Parameter(Mandatory=$true)]$regexReplace,
   $filter = "*",
   [switch]$preview)
{
    $files = Get-ChildItem -Recurse -Filter $filter | Where-object {!$_.psIsContainer -eq $true}
    $index = 1
    $found = 0

    $inTfs = Test-TfsWorkspace

    foreach($file in $files)
    {
        $filePath = $file.FullName

        $percentDone = (($index / $files.Count) * 100)
        Write-Progress -activity "Finding and replacing" -status $file.Name -percentComplete $percentDone

        $fileText = [io.file]::ReadAllText($filePath)
        if($fileText -match $regexFind)
        {
            Write-Host "Replacing in $filePath"

            if (!$preview)
            {
                if ($inTfs)
                {
                    Add-TfsPendingChange -Edit $file.FullName
                }

                $replaced = $fileText -replace $regexFind, $regexReplace
                Set-Content $file.FullName -value $replaced -encoding UTF8
            }

            $found += 1
        }

        $index += 1
    }

    "Replaced in {0} of {1} file{2}." -f $found, ($index - 1), (?: {$index -gt 2} {"s"} {""})
}

The script also depends on the following helper functions.

Test-TfsWorkspace is a simple function that returns true if you are within a TFS workspace, and false otherwise.

set-alias tf "C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\TF.exe" -Scope Global
function global:Test-TfsWorkspace()
{
    tf dir . 1>$null 2>$null
    $?
}

Invoke-Ternary is a handy helper for emulating the ternary ? : operator in powershell.

# ---------------------------------------------------------------------------
# Name:   Invoke-Ternary
# Alias:  ?:
# Author: Karl Prosser
# Desc:   Similar to the C# ? : operator e.g.
#            _name = (value != null) ? String.Empty : value;
# Usage:  1..10 | ?: {$_ -gt 5} {"Greater than 5;$_} {"Not greater than 5";$_}
# ---------------------------------------------------------------------------
set-alias ?: Invoke-Ternary -Option AllScope -Description "PSCX filter alias" -Scope global
filter global:Invoke-Ternary([scriptblock]$decider, [scriptblock]$ifTrue, [scriptblock]$ifFalse)
{
    if (&$decider)
    {
        &$ifTrue
    }
    else
    {
        &$ifFalse
    }
}

References: