To get a simple diff between to files in an external tool, you can use git difftool
.
In a conflict resolution situation, you can also use git mergetool
.
They share a certain set of configuration and usage options, but git mergetool
will actually create files similar to the one you know from Bazaar. The details about this are described in the man pages linked above.
difftool
and mergetool
know some of the common diff and merge tools and can use them without further configuration (e.g. vimdiff, meld, k3diff, etc.), but you can configure your own or use the custom options to change the behaviour of those tools.
You should try to get mergetool
to do what you want (for example, mergetool
can be configured to not delete those files after the merge tool exits, so you can inspect them further). Now that you have a starting point, Google will also help, especially if the man pages are too technical for your taste.
If you run into specific problems, you can open a new question ;)