Add Two Kinds Of Dotted Range Notation as a git til

Author: jbranchaud

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_834 TILs and counting..._
+_835 TILs and counting..._
 
 ---
 
@@ -232,6 +232,7 @@ _834 TILs and counting..._
 - [Stashing Only Unstaged Changes](git/stashing-only-unstaged-changes.md)
 - [Stashing Untracked Files](git/stashing-untracked-files.md)
 - [Switch To A Recent Branch With FZF](git/switch-to-a-recent-branch-with-fzf.md)
+- [Two Kinds Of Dotted Range Notation](git/two-kinds-of-dotted-range-notation.md)
 - [Untrack A Directory Of Files Without Deleting](git/untrack-a-directory-of-files-without-deleting.md)
 - [Untrack A File Without Deleting It](git/untrack-a-file-without-deleting-it.md)
 - [Update The URL Of A Remote](git/update-the-url-of-a-remote.md)

git/two-kinds-of-dotted-range-notation.md

@@ -0,0 +1,35 @@
+# Two Kinds Of Dotted Range Notation
+
+There are two kinds of dotted range notation in git -- `..` and `...`.
+
+If you'd like to view all changes on your current feature branch since checking
+out from `master`, you can use the two-dot notation:
+
+```bash
+❯ git log master..some-feature-branch --oneline
+9e50bff (some-feature-branch) Add second feature change
+b11bb0b Add first feature change
+```
+
+You could also switch the refs around to see what has changed on master since
+checking out:
+
+```bash
+❯ git log some-feature-branch..master --oneline
+c2880f8 (HEAD -> master) Add description to README
+```
+
+Then there is the three-dot notation. This will include all commits from the
+second ref that aren't in the first and all commits in the first that aren't in
+the second.
+
+```bash
+❯ git log master...some-feature-branch --oneline
+c2880f8 (HEAD -> master) Add description to README
+9e50bff (some-feature-branch) Add second feature change
+b11bb0b Add first feature change
+```
+
+See `man git-rev-parse` for more details.
+
+[source](https://stackoverflow.com/a/24186641/535590)