RegexToolBox 4+

I love the simplicity and effectiveness of this Regex app. This makes working with the most complex regex patterns almost fun ;-)

The abilty to save my own patterns inside the app and keep my own catalog is also extermely useful.

If you ever work with Regex, you will find this app very useful!

This is generally a useful app, except it is not perfect.
I used the pattern

^((?!TRACE: ).)*($|\n)
(w null replace)

on:

trace: ggdgfhdfghd
dfasdfsdfsf
trace: ggdgfhdfghd
dfasdfsdfsf
dfasdfsdfsfdfasdfsdfsfdfasdfsdfsf
dfasdfsdfsf

and it stated that the following would be replaced:

dfasdfsdfsf
trace: ggdgfhdfghd
dfasdfsdfsf
dfasdfsdfsfdfasdfsdfsfdfasdfsdfsf
dfasdfsdfsf

which is inaccurate. The 3rd line should also have been replaced.

While it would not have helped in this case, other reg-exp explorers provide a preference panel for case sensitivity, etc.

OK, this program has about as minimal an interface as a program can have. Seems like you should be pasting text into the “Source Text” box and then running your regex against that and seeing results. Problem is, there isn’t an edit menu and the program does not seem to accept a cmd-v keyboard command to paste in your source text. Pretty much dead in the water at this point. I’d say “needs work”.
—
Update: 3/14/15 Latest update (3.15.0301) adds an edit menu so now you are able to get your Source text into the program. Seems to work as advertised now. Developer responded within a week with a fix. Upgrade one star.