Find-InTextFile.ps1

function Find-InTextFile
{
	<#
	.SYNOPSIS
		Performs a find (or replace) on a string in a text file or files.
	.EXAMPLE
		PS> Find-InTextFile -FilePath 'C:\MyFile.txt' -Find 'water' -Replace 'wine'
	
		Replaces all instances of the string 'water' into the string 'wine' in
		'C:\MyFile.txt'.
	.EXAMPLE
		PS> Find-InTextFile -FilePath 'C:\MyFile.txt' -Find 'water'
	
		Finds all instances of the string 'water' in the file 'C:\MyFile.txt'.
	.PARAMETER FilePath
		The file path of the text file you'd like to perform a find/replace on.
	.PARAMETER Find
		The string you'd like to replace.
	.PARAMETER Replace
		The string you'd like to replace your 'Find' string with.
	.PARAMETER UseRegex
		Use this switch parameter if you're finding strings using regex else the Find string will
		be escaped from regex characters
	.PARAMETER NewFilePath
		If a new file with the replaced the string needs to be created instead of replacing
		the contents of the existing file use this param to create a new file.
	.PARAMETER Force
		If the NewFilePath param is used using this param will overwrite any file that
		exists in NewFilePath.
	#>
	[CmdletBinding(DefaultParameterSetName = 'NewFile')]
	param (
		[Parameter(Mandatory = $true)]
		[ValidateScript({ Test-Path -Path $_ -PathType 'Leaf' })]
		[string[]]$FilePath,
		
		[Parameter(Mandatory = $true)]
		[string]$Find,
		
		[Parameter()]
		[string]$Replace,
		
		[Parameter()]
		[switch]$UseRegex,
		
		[Parameter(ParameterSetName = 'NewFile')]
		[ValidateScript({ Test-Path -Path ($_ | Split-Path -Parent) -PathType 'Container' })]
		[string]$NewFilePath,
		
		[Parameter(ParameterSetName = 'NewFile')]
		[switch]$Force
	)
	begin
	{
		$SystemTempFolderPath = Get-SystemTempFolderPath
		if (!$UseRegex.IsPresent)
		{
			$Find = [regex]::Escape($Find)
		}
	}
	process
	{
		try
		{
			Write-Log -Message "$($MyInvocation.MyCommand) - BEGIN"
			foreach ($File in $FilePath)
			{
				if ($Replace)
				{
					if ($NewFilePath)
					{
						if ((Test-Path -Path $NewFilePath -PathType 'Leaf') -and $Force.IsPresent)
						{
							Remove-Item -Path $NewFilePath -Force
							(Get-Content $File) -replace $Find, $Replace | Add-Content -Path $NewFilePath -Force
						}
						elseif ((Test-Path -Path $NewFilePath -PathType 'Leaf') -and !$Force.IsPresent)
						{
							Write-Warning "The file at '$NewFilePath' already exists and the -Force param was not used"
						}
						else
						{
							(Get-Content $File) -replace $Find, $Replace | Add-Content -Path $NewFilePath -Force
						}
					}
					else
					{
						(Get-Content $File) -replace $Find, $Replace | Add-Content -Path "$File.tmp" -Force
						Remove-Item -Path $File
						Rename-Item -Path "$File.tmp" -NewName $File
					}
				}
				else
				{
					Select-String -Path $File -Pattern $Find
				}
			}
			Write-Log -Message "$($MyInvocation.MyCommand) - END"
		}
		catch
		{
			Write-Log -Message "Error: $($_.Exception.Message) - Line Number: $($_.InvocationInfo.ScriptLineNumber)" -LogLevel '3'
			Write-Log -Message "$($MyInvocation.MyCommand) - END"
			$false
		}
	}
}