Update git doc notes

- Convert to Markdown.
- Add an example of using `git grep` with exclude pathspecs and `git ls-tree`.

Author: ngie-eign

docs/git/git-git.md

@@ -0,0 +1,84 @@
+### Creating a local repository for gitorious and pushing back to gitorious
+```
+$ git clone <url> <project>
+$ cd <project>
+# Git needs a file to commit.
+$ touch .gitignore
+$ git add .
+$ git remote add origin <url>
+$ git push origin master
+```
+
+### Fork a github repository on gitorious
+```
+$ git clone <gitorious-url>
+$ git remote add origin <gitorious-url>
+$ git remote add upstream <github-url>
+$ git pull upstream
+$ git push -u origin master
+```
+
+### Pulling / merging from an upstream git repo
+```
+$ git pull upstream
+$ git merge upstream
+# Resolve conflicts if needed
+$ git push master
+```
+
+### How do I clone a remote branch with git?
+```
+$ git checkout -b <branch> remotes/origin/<branch>
+```
+
+http://book.git-scm.com/4_undoing_in_git_-_reset,_checkout_and_revert.html
+http://stackoverflow.com/questions/2389361/git-undo-a-merge
+
+Dumping an old repository to a new repository under a subdirectory, maintaining
+all of the commit history:
+
+### Dump all patches for the commits from the start of time to `HEAD`
+```
+$ cd /old/checkout
+#
+# NB: this might be really funky with binary files or may not work; git-lfs's highly
+#     encouraged!
+$ git format-patch --root HEAD
+```
+
+### Import all commits maintaining core commit metadata/authorship
+
+**Note:** This doesn't maintain committership, unfortunately.
+```
+$ cd /new/checkout
+# Start fresh
+$ git am --abort
+$ git reset --hard
+# Apply all patches in sequence; abort if needed
+$ find -s /old/checkout/ -name \*.patch -exec git am --directory=new/subdir {} \;
+[ $? -ne 0 ] && git am --abort
+```
+
+### List all files tracked by git on HEAD under the include/ directory
+```
+$ git ls-tree -r --name-only HEAD include/
+```
+
+### List all files with DEPRECATED using exclude pathspecs in `git grep` call
+
+List all files that fit the following criteria using `git grep`:
+- contain the string "DEPRECATED"
+- tracked by git on HEAD.
+- that don't end with the following extensions under include/:
+    - .c
+    - .md
+    - .pl
+    - .pod
+```
+$ git grep -lEe DEPRECATED \
+    ':(exclude)*.c' \
+    ':(exclude)*.md' \
+    ':(exclude)*.pl' \
+    ':(exclude)*.pod' \
+    include/
+```