Real-time git diff

I typically like to type up my git commit messages while looking at the git diff.

I very much enjoy the output produced by this little perl add-on to git, and produces output that looks like this from git diff (this is a screenshot of git log -p but you get the idea:

Because of how it highlights out the corresponding parts of the lines that have changed it is very easy to see what's changed. Just wanted to share that because it does not look like a lot of people use it, and for me it beats the hell out of using an external separate diff tool or something like that, because this works over the terminal! It is also quite more unix-pipe-friendly in general than something like vimdiff though vimdiff is quite handy in a pinch as well.

Anyway, the show-and-tell is only tangentially related to the real question here, which is, can I set up a terminal window where I've got the git diff showing, but to have it be dynamic so that when I save a file it can refresh the git diff for me? Basically the idea is to have a terminal window serve as a real-time display of the exact changes I am about to commit, and this way I can just switch straight from my text editor to entering the git commit command while reading the entire set of changes, and to have this workflow also be a possibility on a Linux machine over SSH as well.

That would be a really awesome workflow, and I think a little bit of cmdline fu can get me there, but I'm not really sure where to start. It seems like OS X and Linux would require separate implementations. I found fswatch which might work for me, and apparently that is similar to inotify-watch on Linux. I shouldn't need to set this up on more than just my OS X dev machine, but like I mentioned before, having this capability over SSH would be epic.

Are there any other quick-and-dirty UNIXy approaches to this problem?

回答1:

You would like something like "watch git diff". The "watch" command repeatedly runs a command and shows the first page of output.

You need more than the first page of output, and also you don't want to be moved to the top of the output whenever it updates - you want to constantly view the same offset in the diff until you scroll.

I haven't tried it but you might be able to use "screen" or "tmux" to provide a large virtual screen. (See https://serverfault.com/questions/50772/is-there-a-paging-version-of-watch.)

回答2:

What's wrong with using plain built-in git commit -v which just shows you the full diff of the changes to be committed under the commit message? (And Vim highlights this diff just okay, with stock setup.)