Significant addtions to branching chapter

git-primer.tex

@@ -469,10 +469,128 @@ Let's go ahead and commit those using the following set of commands:
 
 \input{include/branch001}
 
-Notice that we don't have a remote repository at this point, so all we are doing is making commits.
+Notice that we don't have a remote repository at this point, so all we are doing is making commits. Running \texttt{git status} gives us this output:
+
+\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{}]
+On branch main
+nothing to commit, working tree clean
+\end{Verbatim}
+
+Let's suppose we want to make some edits in this file, but we're not sure if we're going to keep them—we're just testing. To do that, we'll create a new branch called ``testbranch'' with this command:
+
+\input{include/branch002}
+
+Git immediately gives us this message:
+
+\begin{Verbatim}[]
+Switched to a new branch 'testbranch'
+\end{Verbatim}
+
+Now we're going to add a new line to \texttt{doc\a.txt} so it looks like this:
+
+\label{doc-aC2}
+\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{doc\_a.txt New Contents}]
+This is line A1.
+This is line A2.
+This is line B1.
+\end{Verbatim}
+
+Now if we run \texttt{git status}, we'll see this:
+
+\begin{Verbatim}[]
+On branch testbranch
+Changes not staged for commit:
+  (use "git add <file>..." to update what will be committed)
+  (use "git restore <file>..." to discard changes in working directory)
+	modified:   doc_a.txt
+
+no changes added to commit (use "git add" and/or "git commit -a")
+\end{Verbatim}
+
+Again, Git provides us with helpful information here. It's telling us that we are on ``testbranch'' and not our main branch, it tells us that we have changes in a file, and that we have yet not committed those changes. What it's not telling us is what those changes are. To do that, we use the \texttt{git diff} command:
+
+\input{include/gitdiff}
+
+Which gives us this output:
+
+\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Output of git diff}]
+diff --git a/doc_a.txt b/doc_a.txt
+index ea9c135..01b52bf 100644
+--- a/doc_a.txt
++++ b/doc_a.txt
+@@ -1,2 +1,3 @@
+ This is line A1.
+ This is line A2.
++This is line A3.
+\end{Verbatim}
+
+In most terminals, this output will be color-coded, which is helpful on the fly, but we have line numbers here to help us. Let's take this line by line to understand what Git is telling us.  
+
+
+\begin{itemize}
+\item Line 1 (\texttt{diff --git a/doc\_a.txt b/doc\_a.txt}) shows us that we are examining two different versions of the same file. Git is calling the original version ``a'' and the new version ``b''
+\item Line 2 (starting with ``\texttt{index}'') is meta data about the files, and is not terribly useful. \texttt{100644} shows that this is a normal file, rather than an executable one (which would be \texttt{100755}) or a symbolic link (which would be \texttt{120000}).
+\item Lines 3 and 4 show that Git is assigning a minus sign (-) to the ``a'' version of the file and a plus sing (+) to the ``b'' version of the file, which it will use starting in line 6.
+\item Line 5 is a \textbf{chunk header}. Git is not going to show you the entire contents of your file, but rather just the chunks that have differences. (Except in our example, which is a very small file.) 
+	\begin{itemize}
+	\item The chunk header starts and ends with \texttt{@@}.
+	\item ``\texttt{-1, 2}'' is actually three separate pieces of information. Git is telling us that it is going to show us 2 lines, starting at line 1, from the ``a'' version of our file (because of the minus sign at the beginning).
+	\item ``\texttt{+1, 3}'' is again three separate pieces of information. Git is telling us that it is going to show us 3 lines, starting at line 1, from the ``b'' version of our file (because of the plus sign at the beginning).
+	\end{itemize}
+\item Lines 6-8 are the lines that are different. Notice that line 8 starts with a plus sign, meaning that this line appears in version ``b'' only. 
+\end{itemize}
+
+Let's make a couple of other changes, and see how this output changes. 
+
+First, let's \textit{delete} the first line (``This is line A1.'').
+
+Second, let's create a new file (which we'll call \texttt{doc\_b.txt}) which will contain a single line of text: ``This is line B1.'' 
+
+Running \texttt{git diff} now gives us slightly different output:
+
+\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Output of git diff}]
+diff --git a/doc_a.txt b/doc_a.txt
+index 01b52bf..505be23 100644
+--- a/doc_a.txt
++++ b/doc_a.txt
+@@ -1,3 +1,2 @@
+-This is line A1.
+ This is line A2.
+ This is line A3.
+\end{Verbatim}
+
+This is similar to before, but now we are seeing that line 6 now has a minus sign in front of it, because that line only exists in the original version of that file. But it doesn't show us any information about \texttt{doc\_b.txt} because file is completely new. 
+
+How does this test branch compare to our main branch? First, let's add both files (\texttt{git add -A}) and make a commit (\texttt{git commit -m "commit message"}). Now we can ask Git to tell us the difference between these two branches using this command:
+
+\input{include/gitdiffbranch}
+
+\begin{Verbatim}[frame=lines, numbers=left, xleftmargin=5mm, framesep=3mm, breaklines=true, label=\fbox{Output of git diff main testbranch}]
+diff --git a/doc_a.txt b/doc_a.txt
+index ea9c135..505be23 100644
+--- a/doc_a.txt
++++ b/doc_a.txt
+@@ -1,2 +1,2 @@
+-This is line A1.
+ This is line A2.
++This is line A3.
+diff --git a/doc_b.txt b/doc_b.txt
+new file mode 100644
+index 0000000..3fc1659
+--- /dev/null
++++ b/doc_b.txt
+@@ -0,0 +1 @@
++This is line B1.
+\end{Verbatim}
+
+Lines 2-8 tell us about ``doc\_a.txt'' and lines 9-15 tells us about ``doc\_b.txt''. 
+
+Notice that line 12 is telling us that the ``a'' version of ``\texttt{doc\_b.txt}'' (that is, the version that exists in the main branch) is ``\texttt{/dev/null}'' which is Git's way of telling us that this file does not exist at all in the main branch. In fact, line 14 shows us \texttt{-0,0} which means that Git is showing us zero lines starting at line zero from the ``a'' version of this file.  
+
+\section{Uses of Branching}
+
+
 
-\todo[inline]{Talk about git \texttt{diff here}.}
-  
 
 \chapter{Collaborating With Yourself — A Guide for Creatives}
 

include/branch002.tex

@@ -0,0 +1,3 @@
+\begin{Verbatim}[]
+$ git checkout -b testbranch
+\end{Verbatim}

include/gitdiff.tex

@@ -0,0 +1,3 @@
+\begin{Verbatim}[]
+$ git diff
+\end{Verbatim}

include/gitdiffbranch.tex

@@ -0,0 +1,3 @@
+\begin{Verbatim}[]
+$ git diff main testbranch
+\end{Verbatim}