Add Find The Date That A File Was Added To The Repo as a git til

git/find-the-date-that-a-file-was-added-to-the-repo.md

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+# Find The Date That A File Was Added To The Repo
+
+The `git log` command has a bunch of flags that you can use to filter
+commits and format their output.
+
+We can get `git log` to only show the date for a commit in the `short`
+format with the following flags:
+
+```bash
+$ git log --pretty=format:"%ad" --date=short
+```
+
+We can also get `git log` to filter commits to just those that have files
+being added:
+
+```bash
+$ git log --diff-filter=A
+```
+
+Like many `git` commands, we can restrict the output to those that match a
+path or file.
+
+```bash
+$ git log -- README.md
+```
+
+If we put all of these together, then we have a one-line command for getting
+the date a specific file was added to the repository:
+
+```bash
+$ git log --pretty=format:"%ad" --date=short --diff-filter=A -- README.md
+2015-02-06
+```
+
+See `man git-log` for more details.