Here are the top few things I learned about git in the first few hours I used it. This is the document I wished I had had, on top of the various introductions floating around. Maybe it will be useful to somebody else.
0. Git handles 400MB of HTML crawl data less gracefully than it handles 700K of Python. But it handles that data more gracefully than `cp` and `rsync` do. 1. Don't `git push` to a repository that actually has a work area. Always use `git pull` instead. `git push` doesn't update the associated working area, or the index either, so if you try to `git commit` in that repository, you will commit a patch that undoes all the stuff you just did. See <http://utsl.gen.nz/talks/git-svn/intro.html> section "Push changes and the working copy". You can solve this with `git reset --mixed HEAD`, or eventually `git reset --hard HEAD` to throw away any changes in the working area. 23:05 < johnw> $ rsync -av .git/ server:/tmp/foo.git/ ; cd /tmp ; git clone ssh://server/tmp/foo.git 23:06 < johnw> that's all you need to setup a remote repository, and to start using it right away 2. `git repack -a -d -f` can achieve some truly astonishing compression ratios. This is how you make git checkouts faster than cp -a or rsync. In my case, three times faster than rsync over a slow network, due to a 7:1 compression ratio. 3. You have to `git add` changed files before you can `git commit` them, or use `git commit -a`, because `git commit` commits things from the index, not your work area. In older versions of Git, you used `git update-index` instead of `git add` on changed files. 4. `git commit` takes an option `--amend` which lets you amend previous commits. 5. `git clone -l` makes a hardlinked clone. 6. git has early-stage support for something called "submodules" in recent versions, similar to svn:externals. And there's an in-development `git hunk-commit` command that might end up in git someday that should add most of Darcs's UI niceness to git. <http://raphael.slinckx.net/files/git-darcs-record> I took the first 125 563 056 bytes of my mailbox and compressed them into 59M with git. However, git (1.4) doesn't seem to work very well with multi-gigabyte quantities. If you're using the Git 1.4 from Debian Stable, you'll want to know to use `init-db` instead of `init`, `repo-config` instead of `config`, and often `update-index` instead of `add`.
