This tutorial will address the source code management (SCM) tool named Git. By following these steps you should learn about the basic usage of Git, which is required for the whole practical course. Furthermore, Git is a great SCM tool, and it's good to know how to use it. During this tutorial, we will follow Alan Turing's thoughts towards developing the Turing Machine.

 More in-depth documentation can be found on the official home page, which mentions books, videos, and links to other tutorials and references.

Creating Commits

1. Read the Git for Computer Scientists introduction (skip this if you are already familiar with Git). 
2. For Linux, Git is available in its own package. Windows users can install msysGit. For MacOS, Git is available as part of Xcode; if you cannot install that, use Git for OSX.

3. Create a local repository for the "Turing Project":

   $ mkdir turing
   $ cd turing
   $ git init
   Initialized empty Git repository in ~/turing/.git/

   $ mkdir turing

   $ cd turing

   $ git init

   Initialized empty Git repository in ~/turing/.git/

   $ mkdir turing
   $ cd turing
   $ git init
   Initialized empty Git repository in ~/turing/.git/

4. Add some content: copy notes.txt to your turing directory.

   $ git add notes.txt
   $ git commit -m "wrote some first notes"
   [master (root-commit) 2e73b34] wrote some first notes
    1 files changed, 5 insertions(+), 0 deletions(-)
    create mode 100644 notes.txt

5. Edit notes.txt:
   
   1. Replace "fixed" with "infinite" in line 1.
   2. Replace "... (TODO)" with "a finite state machine" in line 4.

6. Commit the modified content to your local repository:

   $ git add notes.txt
   $ git commit -m "modified tape length, found a controller for tape head"
   [master 3f28a0e] modified tape length, found a controller for tape head
    1 files changed, 2 insertions(+), 2 deletions(-)

After the preceding steps you have two commits in your local repository, each with one file in the index. You have different options for viewing these commits:

$ git log
commit 3f28a0e473bf3da4aff34a09fed838fe033f3bb5
Author: Miro Spoenemann <msp@informatik.uni-kiel.de>
Date:   Mon Oct 15 14:30:24 2012 +0200

    modified tape length, found a controller for tape head

commit 2e73b34ac44480773fc0e52875b7353a087d8c6d
Author: Miro Spoenemann <msp@informatik.uni-kiel.de>
Date:   Mon Oct 15 12:14:06 2012 +0200

    wrote some first notes
 
$ git show 3f28a0e
commit 3f28a0e473bf3da4aff34a09fed838fe033f3bb5
Author: Miro Spoenemann <msp@informatik.uni-kiel.de>
Date:   Mon Oct 15 14:30:24 2012 +0200

    modified tape length, found a controller for tape head

diff --git a/notes.txt b/notes.txt
index 4ded2b3..bd422b3 100644
--- a/notes.txt
+++ b/notes.txt
@@ -1,5 +1,5 @@
- * A tape with fixed length
+ * A tape with infinite length
  * Tape head can read or write data
  * Tape head can move left or right
- * The head is controlled by ... (TODO)
+ * The head is controlled by a finite state machine

Note that each commit is identified by a looong hash value, but it is possible to use only a prefix when referencing them (if the prefix is not ambiguous): the example above uses 3f28a0e to identify the second commit.