0
1
00:00:00,530 --> 00:00:06,060
Now the first thing we're going to do is open up terminal and inside terminal we're going to navigate
1

2
00:00:06,060 --> 00:00:07,950
to our desktop.
2

3
00:00:07,950 --> 00:00:13,590
So if you're not familiar with the command line and you haven't watched the module on the command line,
3

4
00:00:13,920 --> 00:00:18,330
then I recommend you to take a look at it now because we're going to be using a lot of the commands
4

5
00:00:18,330 --> 00:00:20,760
to create directories and navigate around.
5

6
00:00:20,760 --> 00:00:25,930
So if you're not yet familiar then it's a good time to take a look at that.
6

7
00:00:25,950 --> 00:00:33,540
So the first thing I'm going to do is I'm going to cd into my desktop. And here I'm going to create a
7

8
00:00:33,540 --> 00:00:43,950
new directory called Story. Then I'm going to cd into this Story directory and if I show you with ls you 
8

9
00:00:43,950 --> 00:00:45,800
can see that it's completely empty.
9

10
00:00:45,930 --> 00:00:50,360
And similarly inside Finder I can show you the same thing.
10

11
00:00:50,370 --> 00:00:54,560
So let's go ahead and create some text files.
11

12
00:00:54,600 --> 00:00:59,580
So I'm going to use touch to create a file called chapter1.txt.
12

13
00:00:59,760 --> 00:01:07,710
And then I'm going to open chapter1.txt and you can either do this by simply writing open and it'll open
13

14
00:01:07,710 --> 00:01:11,820
it inside the default application which is TextEdit on a Mac,
14

15
00:01:12,060 --> 00:01:18,010
alternatively you can use a text editor within the terminal, for example Vim.
15

16
00:01:18,150 --> 00:01:21,710
Now this is only for people who are really familiar with this.
16

17
00:01:21,720 --> 00:01:23,990
So it's totally up to you what you decide to use.
17

18
00:01:24,030 --> 00:01:30,150
But if you are not familiar with using terminal based editors, then it's probably a good idea to just
18

19
00:01:30,150 --> 00:01:33,550
stick with the open command and use TextEdit.
19

20
00:01:33,870 --> 00:01:42,720
So let's go ahead and open chapter1 and let's write something inside, shall we?
20

21
00:01:43,010 --> 00:01:45,230
Okay, so that's my masterpiece done.
21

22
00:01:45,420 --> 00:01:46,910
Going to go ahead and hit save
22

23
00:01:46,950 --> 00:01:49,450
and I'm going to quit TextEdit.
23

24
00:01:49,520 --> 00:01:53,140
So that was our first chapter done.
24

25
00:01:53,330 --> 00:02:02,420
So now let's create a Git local repository and start tracking some of these file changes. So to initialize
25

26
00:02:02,420 --> 00:02:06,290
Git we simply write git init.
26

27
00:02:06,290 --> 00:02:12,440
And as you can see it's initialized and empty Git repository inside the story directory.
27

28
00:02:12,440 --> 00:02:17,260
Now if you have a look inside Finder you actually can't see this .git at all.
28

29
00:02:17,270 --> 00:02:18,870
But as we learned before
29

30
00:02:18,920 --> 00:02:20,640
if you use ls -a
30

31
00:02:20,870 --> 00:02:26,540
you can see all the hidden files and you can see that .git is right there and it's going to be used
31

32
00:02:26,660 --> 00:02:32,270
to track all your changes, to commit your changes and to perform version control.
32

33
00:02:32,270 --> 00:02:38,060
So we're currently inside the story directory and you can also call this the working directory.
33

34
00:02:38,060 --> 00:02:45,200
So as I mentioned before, using Git and learning about version control it comes with some of its own terminology
34

35
00:02:45,290 --> 00:02:46,430
and language.
35

36
00:02:46,520 --> 00:02:51,320
So I'm going to try and debunk and simplify a lot of these terms that you'll come across just so that
36

37
00:02:51,320 --> 00:02:55,660
we can all be on the same page and we all understand what's going on.
37

38
00:02:55,670 --> 00:03:01,640
So currently we are inside the working directory which is the story directory.
38

39
00:03:02,000 --> 00:03:07,700
And here in order to start tracking the changes of my files
39

40
00:03:07,700 --> 00:03:09,740
for example chapter1.txt,
40

41
00:03:09,920 --> 00:03:15,320
then I need to add this file to what's called a staging area.
41

42
00:03:15,740 --> 00:03:23,180
And that is basically a intermediate place where you can pick and choose which files inside your working
42

43
00:03:23,180 --> 00:03:26,220
directory that you want to commit.
43

44
00:03:26,270 --> 00:03:33,170
So to see what's currently inside your staging area, you can use the git status command. And it shows
44

45
00:03:33,170 --> 00:03:39,560
you that there are untracked files which will be shown in red and this is something that simply inside
45

46
00:03:39,560 --> 00:03:41,020
your working directory,
46

47
00:03:41,030 --> 00:03:42,270
so inside here,
47

48
00:03:42,470 --> 00:03:45,310
but it's not yet in the staging area.
48

49
00:03:45,560 --> 00:03:52,520
So in order to add it to the staging area and to start tracking changes in it, then we have to use the
49

50
00:03:52,520 --> 00:03:54,030
command git
50

51
00:03:54,060 --> 00:03:56,840
add. So we're going to type git add 
51

52
00:03:57,170 --> 00:03:58,880
and we're going to type the filename.
52

53
00:03:58,880 --> 00:04:01,730
So in this case it's chapter1.txt.
53

54
00:04:01,910 --> 00:04:08,660
So go ahead and hit enter and then if we try using git status again you can see that that file has been
54

55
00:04:08,750 --> 00:04:11,770
added as a new file and it is now green.
55

56
00:04:11,780 --> 00:04:16,330
So this is now in the staging area and it's ready to be committed.
56

57
00:04:16,340 --> 00:04:20,210
So let's go ahead and commit this under version control.
57

58
00:04:20,210 --> 00:04:28,360
So the command is git commit and I'm going to use the -m flag to add a commit message.
58

59
00:04:28,430 --> 00:04:31,540
So the commit message is really really important.
59

60
00:04:31,580 --> 00:04:38,010
It's something that helps you keep track of what changes you have made in each commit.
60

61
00:04:38,090 --> 00:04:47,150
So when you create a new save point, you want to be as explicit as possible about what changes were made
61

62
00:04:47,180 --> 00:04:50,300
between the last save point and this current save point.
62

63
00:04:50,300 --> 00:04:58,340
So for our initial commit we can use something very simple like Initial Commit. And this shows that this
63

64
00:04:58,340 --> 00:04:59,830
is our starting point.
64

65
00:05:00,050 --> 00:05:05,870
Alternatively if you want to be slightly more specific because in our case we've actually completed
65

66
00:05:05,870 --> 00:05:06,890
chapter1,
66

67
00:05:07,040 --> 00:05:11,100
so you can write Complete Chapter 1.
67

68
00:05:11,120 --> 00:05:16,490
Now the thing that you'll realize is that usually with commit messages they are written in the present
68

69
00:05:16,490 --> 00:05:18,550
tense and this is the best practice.
69

70
00:05:18,560 --> 00:05:25,160
So whereas it would probably make more sense I guess at least in my head anyways to write completed
70

71
00:05:25,220 --> 00:05:28,090
chapter 1 as this save point,
71

72
00:05:28,190 --> 00:05:32,630
it's actually by convention that you should always use the present tense.
72

73
00:05:32,630 --> 00:05:36,860
So it's like you are doing it now. You're submitting your changes now.
73

74
00:05:36,950 --> 00:05:44,150
So let's go ahead and hit enter to make our first commit and you can see what commits you have made
74

75
00:05:44,150 --> 00:05:47,230
by using the git log command.
75

76
00:05:47,510 --> 00:05:53,200
So you can see that this commit was made at this time by this person.
76

77
00:05:53,490 --> 00:06:01,730
And it also has a hash and this hash uniquely identifies this particular commit. And then right at the
77

78
00:06:01,730 --> 00:06:06,640
end you see this commit message of what this save point was all about.
78

79
00:06:07,820 --> 00:06:12,260
So now I'm going to go ahead and create two more chapters.
79

80
00:06:12,290 --> 00:06:25,400
So let's just create chapter2.txt and chapter3.txt and now we have three chapters
80

81
00:06:25,670 --> 00:06:29,580
and I'm going to go in and change some of these text files.
81

82
00:06:29,630 --> 00:06:30,980
So let's say...
82

83
00:06:41,260 --> 00:06:43,900
Okay, that's chapter 2 done.
83

84
00:06:43,900 --> 00:06:49,330
And finally let's go ahead and just open chapter 3 and edit that as well.
84

85
00:07:01,090 --> 00:07:01,390
All right.
85

86
00:07:01,400 --> 00:07:03,670
So all three files have been changed.
86

87
00:07:03,710 --> 00:07:09,020
And over here in Finder you can actually get a quick peek at what the contents are which is going to
87

88
00:07:09,020 --> 00:07:14,720
be really useful for me to be able to demonstrate to you what Git is doing behind the background.
88

89
00:07:14,750 --> 00:07:20,810
So now let's go ahead and add these two new files to our staging area.
89

90
00:07:20,810 --> 00:07:28,130
So again if we use git status, you can see that there's two files that are untracked which are only in
90

91
00:07:28,130 --> 00:07:31,940
the working directory and not yet inside the staging area.
91

92
00:07:32,240 --> 00:07:38,580
So we can put it into the staging area by simply adding each of them as we did before,
92

93
00:07:38,600 --> 00:07:45,370
git add and writing something like chapter2.txt and then doing git add chapter3.txt.
93

94
00:07:45,590 --> 00:07:51,890
But as you can imagine if you have quite a few files then it can get incredibly tedious having to do
94

95
00:07:51,890 --> 00:07:53,530
this one by one.
95

96
00:07:53,540 --> 00:07:56,030
So of course there is a better way.
96

97
00:07:56,030 --> 00:08:01,820
So instead of adding these files one by one, we can actually simply just say git add and then use the
97

98
00:08:01,820 --> 00:08:07,010
to specify everything inside this current directory,
98

99
00:08:07,010 --> 00:08:09,780
so everything inside the story directory.
99

100
00:08:10,010 --> 00:08:14,860
So now if I go ahead and hit enter and then let's go to git status again,
100

101
00:08:14,870 --> 00:08:21,290
you can see that there's two new files that have been added to the staging area. And now we're going
101

102
00:08:21,290 --> 00:08:26,570
to commit those two files to a new commit to a new save point.
102

103
00:08:26,870 --> 00:08:30,060
And you know what to do. If you're following along with me
103

104
00:08:30,080 --> 00:08:31,420
go ahead and give it a go.
104

105
00:08:35,500 --> 00:08:35,830
All right.
105

106
00:08:35,830 --> 00:08:38,480
So how is that? If you remember, 
106

107
00:08:38,500 --> 00:08:39,890
the command is
107

108
00:08:39,940 --> 00:08:48,730
git commit and we're going to use the -m to specify a commit message. And we're going to write a message
108

109
00:08:49,150 --> 00:08:58,690
that is in the present tense. So let's say complete chapter 2 and 3.
109

110
00:08:58,900 --> 00:09:05,550
So that's everything I've done between the initial commit and this commit
110

111
00:09:05,560 --> 00:09:09,950
the only difference is the fact that I've completed now chapter 2 and chapter 3.
111

112
00:09:10,210 --> 00:09:13,120
So let's go ahead and and hit enter.
112

113
00:09:13,510 --> 00:09:15,720
So again let's check it out
113

114
00:09:15,730 --> 00:09:23,830
using git log. We can see that we now have two commits both with different hashes because they are unique
114

115
00:09:23,890 --> 00:09:24,960
and they are different.
115

116
00:09:25,240 --> 00:09:32,950
So the initial one was complete chapter 1 and it was done at this time. And then later on about five
116

117
00:09:32,950 --> 00:09:36,060
minutes later I completed chapter 2 and 3
117

118
00:09:36,130 --> 00:09:38,140
and that was the second commit.
118

119
00:09:38,440 --> 00:09:41,170
And this is where we are at right now.
119

120
00:09:41,200 --> 00:09:44,800
So you can see by the head by this word HEAD
120

121
00:09:45,100 --> 00:09:49,420
this is the position or the current state that we are in.
121

122
00:09:49,420 --> 00:09:52,800
So I just want to quickly recap what we've just done.
122

123
00:09:52,900 --> 00:09:58,380
So we created a file in our working directory inside our story directory.
123

124
00:09:58,570 --> 00:10:05,960
So the working directory is the folder or the directory where you initialize your Git repository.
124

125
00:10:06,040 --> 00:10:10,340
When we said git init, we did that inside the story directory.
125

126
00:10:10,390 --> 00:10:12,470
So that becomes a working directory.
126

127
00:10:12,700 --> 00:10:18,850
And from now on Git is going to try and track the changes that it sees between the working directory
127

128
00:10:19,240 --> 00:10:22,020
and the local repository.
128

129
00:10:22,420 --> 00:10:31,020
So in the beginning we created a file inside our working directory inside story and then we used git
129

130
00:10:31,010 --> 00:10:34,270
add to push it to the staging area.
130

131
00:10:34,270 --> 00:10:39,700
Now the reason why there is this intermediate staging area because you might wonder, why not just go
131

132
00:10:39,700 --> 00:10:42,270
from the working directory straight to the repository?
132

133
00:10:42,460 --> 00:10:44,640
Why do we need this extra step?
133

134
00:10:44,800 --> 00:10:52,390
Well sometimes you might not want to add all of your files to be tracked or all of your files to be
134

135
00:10:52,390 --> 00:10:53,510
committed.
135

136
00:10:53,560 --> 00:10:59,190
So the staging area is a good place to try and figure out what are the things that you want Git to ignore
136

137
00:10:59,350 --> 00:11:02,070
and what are the things that you want to be tracked.
137

138
00:11:02,140 --> 00:11:09,130
So once we've used git add we've put all file into the staging area and we're happy with the changes
138

139
00:11:09,130 --> 00:11:17,120
that we are going to commit, then the next step is to go ahead and commit it using the git commit command.
139

140
00:11:17,140 --> 00:11:25,660
So now our file is inside our local repository. so that .git and that version is given a name through
140

141
00:11:25,660 --> 00:11:27,310
the commit message.
141

142
00:11:27,310 --> 00:11:35,470
So that means that even if we've messed up our file, we can still use the last version that's under version
142

143
00:11:35,470 --> 00:11:43,720
control and we can use a special command called git checkout to revert back or rollback to the last
143

144
00:11:43,780 --> 00:11:46,210
position in our local repository.
144

145
00:11:46,330 --> 00:11:52,010
So let me show you what that looks like in the command line and how we would do that in practice.
145

146
00:11:52,030 --> 00:11:57,370
So at the moment, I've got three nicely written chapters and I have a feeling my book is going to be
146

147
00:11:57,370 --> 00:11:58,370
a big seller.
147

148
00:11:58,390 --> 00:12:06,460
So now let's say that I have you know I've been working on chapter 3 and I have completely messed
148

149
00:12:06,460 --> 00:12:13,840
everything up and just you know fell asleep on my keyboard and I happened to have saved my file.
149

150
00:12:13,840 --> 00:12:21,140
And now if you have a look at it, it's now just mumbo jumbo and I've ruined my masterpiece. But fear not
150

151
00:12:21,190 --> 00:12:28,220
because we have version control and we have Git enabled so we have nothing to worry about.
151

152
00:12:28,540 --> 00:12:33,600
I can actually revert the changes that I've made locally in my working directory.
152

153
00:12:33,730 --> 00:12:39,230
So at this point you can use git status to see that we have modifications in our chapter3.
153

154
00:12:39,350 --> 00:12:44,740
txt file that have not yet been committed or added to the staging area.
154

155
00:12:44,800 --> 00:12:50,790
So if we wanted to we can actually revert this back to it's previous glory.
155

156
00:12:51,190 --> 00:12:57,850
But before we do that, we can use a git command to check out one of the differences between the current
156

157
00:12:57,850 --> 00:13:02,880
version of chapter 3 and the last save point in our Git repository.
157

158
00:13:03,190 --> 00:13:06,760
So to do that you can use the command git diff
158

159
00:13:06,910 --> 00:13:12,390
so the difference, and we'll give it the chapter 3 file name.
159

160
00:13:12,610 --> 00:13:17,140
And if you hit enter, you can see that this is the part that was deleted,
160

161
00:13:17,140 --> 00:13:23,810
so the part in red, and then this was the part that was added which is our gobbledegoop.
161

162
00:13:23,980 --> 00:13:29,560
So now if I've looked at these differences, it might just be that you know there's only a few mistakes
162

163
00:13:29,890 --> 00:13:35,970
in my new version of chapter 3 and I just want to maybe copy some things over or have a look at how
163

164
00:13:35,970 --> 00:13:41,340
I did certain things previously and change my current file.
164

165
00:13:41,670 --> 00:13:46,860
But other times, it might be that you know it's just you want to touch the new file.
165

166
00:13:46,860 --> 00:13:49,070
You just don't want anything to do with it
166

167
00:13:49,080 --> 00:13:52,860
and you would much rather roll back to the previous version.
167

168
00:13:52,920 --> 00:13:59,310
So if you want to do that then there is a command called git checkout that is going to be really really
168

169
00:13:59,310 --> 00:14:00,650
useful for you.
169

170
00:14:00,750 --> 00:14:03,000
So git checkout
170

171
00:14:03,150 --> 00:14:07,890
and then we're going to specify the name of the file that we want to checkout which is chapter3.
171

172
00:14:07,890 --> 00:14:14,520
txt. And if you just watch over here which is the preview of the current version of chapter3.txt,
172

173
00:14:15,120 --> 00:14:22,980
once I hit enter on this command that basically asks to roll back this chapter 3 to the last version
173

174
00:14:23,010 --> 00:14:26,520
that was committed in our local repository.
174

175
00:14:26,520 --> 00:14:33,840
So if I hit enter, you can see that almost immediately my chapter 3 has been restored to its previous
175

176
00:14:34,380 --> 00:14:35,550
glorious state.
176

177
00:14:35,760 --> 00:14:41,340
And this is the version of chapter 3 at the last check point at which I committed it.
177

178
00:14:41,580 --> 00:14:45,940
So that was this one which is completed chapter 2 and 3.
178

179
00:14:45,960 --> 00:14:53,820
So whereas in this lesson we've looked mostly at local implementations of Git so saving these versions
179

180
00:14:53,910 --> 00:14:56,810
on our computer locally, in the next lesson
180

181
00:14:56,820 --> 00:15:02,520
I'm going to talk about GitHub and creating remote repositories. So I'll see you there.