PowerGREP is not available for Mac but there are plenty of alternatives that runs on macOS with similar functionality. The best Mac alternative is DocFetcher, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to PowerGREP and 12 are available for Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to PowerGREP are grep (Free, Open Source), The Silver Searcher (Free, Open Source), FAR - Find And Replace (Free, Open Source) and Find Any File (Paid).
String Replacer for Mac allows to find and replace a list of strings inside files and folders directly or in batch mode. It allows to operate on multiple files using a multiple string couple replacement list. It works with just a single click or using drag and drop.
TextSeek helps you search document contents for Windows and MacOS within seconds, inlcuding PDF, Word, Excel, Powerpoint and other formats. The core feature is that TextSeek can perform search character-by-character with no omission.