During the last couple of days  I had to replace some words in several text files so I decided to write a Power Shell script to perform this task. Below is the code snippet I used:

$files = get-childitem *.txt
foreach ($file in $files)
{
    $content = Get-Content -path $file
    $content | foreach {$_ -replace "oldText","newText" } | Set-Content $file
}

Enjoy it!