Mercurial has some useful commands that will help you to recover from some common mistakes.

The hg revert command lets you undo changes that you have made to your working directory. For example, if you hg add a file by accident, just run hg revert with the name of the file you added, and while the file won’t be touched in any way, it won’t be tracked by Mercurial any longer, either. You can also use hg revert to get rid of erroneous changes to a file.

It is helpful to remember that the hg revert command is useful for changes that you have not yet committed. Once you’ve committed a change and then decide it was a mistake, you can still do something about it, though your options may be more limited.