to be written...

To illustrate git in action, I pulled text files from a great book, ThinkPython2, using wget.

in Terminal

brew install git
brew link git

in Terminal

brew install wget
mkdir ThinkPython2
cd ThinkPython2
wget -r -np -k -nd http://greenteapress.com/thinkpython2/html/

in Terminal

git init
git add .
git commit -am 'initial commit'

in Terminal

git checkout -b move-images-into-a-folder
mkdir images
mv *.png images/

With Sublimetext installed, in Terminal

subl .

Use ⇧⌘f call out find and replace panel.

(Atom editor has an unsolved issue on finding and replacing with regex...)

find:

img src="

where:

*.html

replace:

img src="images/

in Terminal

git status
git add .
git status
git commit -am 'move images into a folder'
git checkout master
git merge move-images-into-a-folder
git log

git checkout -b add-bootstrap

find:

<link rel="stylesheet" type="text/css" href="thinkpython2.css">

where:

*.html

replace

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" integrity="sha384-fLW2N01lMqjakBkx3l/M9EahuwpSfeNvV63J5ezn3uZzapT0u7EYsXMjQV+0En5r" crossorigin="anonymous">
<link rel="stylesheet" type="text/css" href="thinkpython2.css">

find:

</html>

where:

*.html

replace:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min> .js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVq> OtnepnHVP9aJ7xS" crossorigin="anonymous"></script>
</html>

with regex enabled

find:

<a href="(.*)"><img.*\s\Sa href="(.*)"><img.*\s\Sa href="(.*)"><img.*\s\Shr>

where:

*.html

replace:

 <nav class="navbar navbar-default navbar-fixed-top">
 <div class="container-fluid">
 <!-- Brand and toggle get grouped for better mobile display -->
 <div class="navbar-header">
 <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
 <span class="sr-only">Toggle navigation</span>
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 </button>
 <a class="navbar-brand" href="#"><strong>Think Python</strong> - How to Think like a Computer Scientist (2e) <em>by Allen B. Downey</em></a>
 </div>
 <div>
 <ul class="nav navbar-nav navbar-right">
 <li><a href="http://greenteapress.com/thinkpython2/html/index.html"><span class="glyphicon glyphicon glyphicon-book" aria-hidden="true"></span></a></li>
 <li><a href="1ドル"><span class="glyphicon glyphicon glyphicon-menu-left" aria-hidden="true"></span></a></li>
 <li><a href="index.html"><span class="glyphicon glyphicon glyphicon-home" aria-hidden="true"></span></a></li>
 <li><a href="3ドル"><span class="glyphicon glyphicon glyphicon-menu-right" aria-hidden="true"></span></a></li>
 <li><a href="http://amzn.to/1VUYQUU"><span class="glyphicon glyphicon glyphicon-shopping-cart" aria-hidden="true"></span></a></li>
 </ul>
 <div>
 </div><!-- /.container-fluid -->
 </nav>

find:

<a href="thinkpython2022.html"><img src="images/back.png" ALT="Previous"></a>
<a href="index.html"><img src="images/up.png" ALT="Up"></a>
<hr>

where:

thinkpython2023.html

replace:

 <nav class="navbar navbar-default navbar-fixed-top">
 <div class="container-fluid">
 <!-- Brand and toggle get grouped for better mobile display -->
 <div class="navbar-header">
 <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
 <span class="sr-only">Toggle navigation</span>
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 </button>
 <a class="navbar-brand" href="#"><strong>Think Python</strong> - How to Think like a Computer Scientist (2e) <em>by Allen B. Downey</em></a>
 </div>
 <div>
 <ul class="nav navbar-nav navbar-right">
 <li><a href="http://greenteapress.com/thinkpython2/html/index.html"><span class="glyphicon glyphicon glyphicon-book" aria-hidden="true"></span></a></li>
 <li><a href="thinkpython2022.html"><span class="glyphicon glyphicon glyphicon-menu-left" aria-hidden="true"></span></a></li>
 <li><a href="index.html"><span class="glyphicon glyphicon glyphicon-home" aria-hidden="true"></span></a></li>
 <li><a href="thinkpython2023.html"><span class="glyphicon glyphicon glyphicon-menu-right" aria-hidden="true"></span></a></li>
 <li><a href="http://amzn.to/1VUYQUU"><span class="glyphicon glyphicon glyphicon-shopping-cart" aria-hidden="true"></span></a></li>
 </ul>
 <div>
 </div><!-- /.container-fluid -->
 </nav>

in index.html, insert before <table>

 <nav class="navbar navbar-default navbar-fixed-top">
 <div class="container-fluid">
 <!-- Brand and toggle get grouped for better mobile display -->
 <div class="navbar-header">
 <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
 <span class="sr-only">Toggle navigation</span>
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 <span class="icon-bar"></span>
 </button>
 <a class="navbar-brand" href="#"><strong>Think Python</strong> - How to Think like a Computer Scientist (2e) <em>by Allen B. Downey</em></a>
 </div>
 <div>
 <ul class="nav navbar-nav navbar-right">
 <li><a href="http://greenteapress.com/thinkpython2/html/index.html"><span class="glyphicon glyphicon glyphicon-book" aria-hidden="true"></span></a></li>
 <li><a href="index.html"><span class="glyphicon glyphicon glyphicon-menu-left" aria-hidden="true"></span></a></li>
 <li><a href="index.html"><span class="glyphicon glyphicon glyphicon-home" aria-hidden="true"></span></a></li>
 <li><a href="thinkpython2001.html"><span class="glyphicon glyphicon glyphicon-menu-right" aria-hidden="true"></span></a></li>
 <li><a href="http://amzn.to/1VUYQUU"><span class="glyphicon glyphicon glyphicon-shopping-cart" aria-hidden="true"></span></a></li>
 </ul>
 <div>
 </div><!-- /.container-fluid -->
 </nav>

find:

<hr>\s\Sa href="(.*)"><img.*\s\Sa href="(.*)"><img.*\s\Sa href="(.*)"><img.*\s

where:

*.html

replace with nothing:

find:

<hr>\s\Sa href="(.*)"><img.*\s\Sa href="(.*)"><img.*\s

where:

*.html

replace with nothing:

find:

<a href="http://amzn.to/1VUYQUU">Buy this book at Amazon.com</a>

where:

*.html

replace with nothing:

in Terminal

git add .
git commit -am 'menu added'
git checkout master
git merge add-bootstrap
git log

in Terminal

git checkout -b content

find:

where:

*.html

replace:

<td valign="top" width="100" bgcolor="#b6459a" id="col-left">

find:

where:

*.html

replace:

<td width=130 valign="top" id="col-right">

find:

<td valign="top" width="600" style="padding: 20px 20px;">

where:

*.html

replace:

<td valign="top" id="content">

append thinkpython2.css

body{
 font-family: "Open Sans";
 font-size: 18px;
 padding-top: 60px;
 max-width: 800px;
 margin: 0 auto;
 margin-bottom:10em;
 background-color: #eee;
}
blockquote {
 border-left: 0px solid #eee;
}
pre.verbatim {
 font-family: "Courier New";
 margin: 10px auto;
 font-size: 16px;
}
table.c000 {
 margin: 12px auto;
}

in Terminal

git add .
git commit -am 'content cleaned'
git checkout master
git merge content