In TextPipe Replace filters, choosing Exact as the pattern type does not do "what it says on the can".
I was processing USFM files - and these contain lots of semantic tags identified by the reverse solidus.
You can see the USFM Reference at http://paratext.org/usfm
Now suppose I need to match exactly the tag \tc1 (Table cell in column 1).
Match fails because TextPipe sees the \t part of \tc1 as a tab character. This is deeply frustrating.
Now the developers of the open source Unicode text editor Notepad++ certainly perceived that there was a problem.
If you examine their search dialog, you'll see that they distinguish three kinds of Search Mode:
Extended (\n, \r, \t, \0, \x ...)
With Exact selected, the pattern \tc1 will be searched as an exact "printable characters" text match.
With Extended selected, the patterm \tc1 will be search as a tab followed by the characters c1.
In TextPipe, there is just confusion, because the user is misled by the use of the word "Exact".
What needs to be done, IMHO, is for TextPipe to follow the example of Notepad++ and distinguish between Exact and Extended.