If you want matching quotes and are happy removing the echo base_url
piece, simply ensure the quotes in the replace in these lines are double instead of single quotes. We were simply inconsistent there and this is the first time it's been pointed out.
https://github.com/h5bp/ant-build-script/blob/master/build.xml#L692-L696
And then please submit a pull request so everyone can have some consistency in their lives. :)
I'm not sure what's happening in your first example. The replace (as you can see) just uses single quotes. If we were mismatching them for everyone there'd be a lot more noise around it. I'll have to test it. Feel free to open an issue on the repo so that I have something to track to.