1 00:00:00,000 --> 00:00:04,425 [MUSIC] 2 00:00:04,425 --> 00:00:09,324 Let us now explore some basic Git commands that are very useful for 3 00:00:09,324 --> 00:00:11,474 us in this specialization. 4 00:00:11,474 --> 00:00:15,055 There is lot more to Git than what we cover in this exercise. 5 00:00:18,130 --> 00:00:23,231 To get started, go to your convenient location on your computer, 6 00:00:23,231 --> 00:00:26,523 and then create a folder named git-test. 7 00:00:30,140 --> 00:00:34,408 Then open this folder in your favorite editor. 8 00:00:37,895 --> 00:00:42,585 Here I have the git-test folder that we just created 9 00:00:42,585 --> 00:00:45,390 open in my Visual Studio Code. 10 00:00:45,390 --> 00:00:51,915 Let me add a file to this folder named index.html. 11 00:00:54,122 --> 00:01:00,430 Now you can see that I have added in some HTML code into this index.html file. 12 00:01:00,430 --> 00:01:06,507 Let's save the changes, now let's switch to our command line. 13 00:01:06,507 --> 00:01:10,903 At the command line, go to the git-test folder, and 14 00:01:10,903 --> 00:01:15,860 let's initialize this folder to be a Git repository. 15 00:01:15,860 --> 00:01:19,800 So to do that, add the command line, type, git init. 16 00:01:21,620 --> 00:01:27,710 Now this folder has been initialized to be a Git repository, so 17 00:01:27,710 --> 00:01:32,650 this is our first Git command that we have learned, git init. 18 00:01:32,650 --> 00:01:36,320 This initializes the current folder as a Git repository, and 19 00:01:36,320 --> 00:01:42,380 when it initializes the folder, it will mark that folder as a master. 20 00:01:42,380 --> 00:01:47,770 This is the master branch for my Git, now let's not worry about branches and 21 00:01:47,770 --> 00:01:51,000 so on, we will not deal with that in this course. 22 00:01:51,000 --> 00:01:55,738 We will only be working with the master branch in this particular specialization, 23 00:01:55,738 --> 00:01:58,500 so this would be marked as the master. 24 00:01:58,500 --> 00:02:02,060 Now, this is the initial point of our repository, 25 00:02:03,770 --> 00:02:08,410 the next command that we're going to look at is git status. 26 00:02:08,410 --> 00:02:12,600 If you type git status in the command line, it'll tell you the current status of 27 00:02:12,600 --> 00:02:17,460 the folder, so let's do that at the command line and see what it shows. 28 00:02:19,470 --> 00:02:23,395 At the command line, type git status, and 29 00:02:23,395 --> 00:02:28,945 read the information that is typed out on the command window. 30 00:02:28,945 --> 00:02:33,943 You see that it says, On branch master, so that is the master branch that we are on, 31 00:02:33,943 --> 00:02:40,690 and it says, untracked files, and then shows index.html in red. 32 00:02:40,690 --> 00:02:44,458 On your specific computer, it may be using different colors or 33 00:02:44,458 --> 00:02:49,040 represent this differently, but this is what it shows on my Mac. 34 00:02:49,040 --> 00:02:54,040 So now this index.html file that we have just created in this folder 35 00:02:54,040 --> 00:02:58,140 is now not been added to our Git repository. 36 00:02:58,140 --> 00:03:01,335 So let's go ahead and add that file to the Git repository. 37 00:03:01,335 --> 00:03:07,510 So to do that, we say, git add, and you can simply say dot, 38 00:03:07,510 --> 00:03:12,350 which means that all the files in the current directory will be added to 39 00:03:12,350 --> 00:03:17,680 what is called as the staging area of my Git repository. 40 00:03:17,680 --> 00:03:22,880 So now if I again type, git status, you will see 41 00:03:22,880 --> 00:03:27,910 that the file index.html is marked in green, and 42 00:03:27,910 --> 00:03:35,130 it says changes to be committed there, and then shows the file name. 43 00:03:35,130 --> 00:03:35,672 And then, 44 00:03:35,672 --> 00:03:39,601 so that means that this file is now ready to be committed to my Git repository. 45 00:03:41,438 --> 00:03:46,856 So the next command that we saw was git add, by using git add, 46 00:03:46,856 --> 00:03:51,190 you can add file or folders to the staging area. 47 00:03:51,190 --> 00:03:57,250 So once you add it to the staging area, then you can commit that snapshot 48 00:03:57,250 --> 00:04:03,100 of our folder status to our Git repository. 49 00:04:03,100 --> 00:04:06,460 So that means that when you do the git commit, 50 00:04:08,130 --> 00:04:12,610 what this command will do is commit the current 51 00:04:12,610 --> 00:04:17,200 state of our folders into our Git repository. 52 00:04:17,200 --> 00:04:21,780 So all the files, as they exist at the moment, once they have been staged 53 00:04:21,780 --> 00:04:25,560 using the git add, then they will be committed through a Git repository, 54 00:04:25,560 --> 00:04:29,510 then we execute the git command folder. 55 00:04:29,510 --> 00:04:33,580 So, at this point, when we execute the git command, 56 00:04:33,580 --> 00:04:38,373 then our initial state will now be changed to the first commit to 57 00:04:38,373 --> 00:04:42,369 the Git repository, so let's go ahead and do that. 58 00:04:45,208 --> 00:04:50,261 Back at the command prompt, let's type git commit, 59 00:04:50,261 --> 00:04:54,880 and then we can even add a message to our commit. 60 00:04:54,880 --> 00:04:59,275 So I'm going to say git commit -m "first commit", 61 00:04:59,275 --> 00:05:03,879 because this is our first commit to our Git repository. 62 00:05:03,879 --> 00:05:10,106 So when I do that, it says, okay, one file has been added to the Git repository and 63 00:05:10,106 --> 00:05:15,300 some other information will be typed out onto the command window. 64 00:05:15,300 --> 00:05:20,440 So let's now check, again, git status, 65 00:05:20,440 --> 00:05:26,220 and now you see that it says, nothing to commit, working directory is clean. 66 00:05:26,220 --> 00:05:31,230 So what that means is that the current state of my working directory or 67 00:05:31,230 --> 00:05:35,860 working folder has been committed to the Git repository. 68 00:05:35,860 --> 00:05:41,050 So a snapshot has been committed to my Git repository, now I can type the next 69 00:05:41,050 --> 00:05:47,200 command, called git log --oneline. 70 00:05:47,200 --> 00:05:52,156 And see that it shows a number there, an eight digit number there, and 71 00:05:52,156 --> 00:05:57,545 it also shows the message that we put in our commit saying "first commit". 72 00:05:57,545 --> 00:06:03,340 So that is the log of all the commits that have been put into my Git repository. 73 00:06:05,120 --> 00:06:08,900 So going back to our next git command, 74 00:06:08,900 --> 00:06:14,094 we saw that git log --oneline 75 00:06:14,094 --> 00:06:18,540 will show us a brief log of all the commits. 76 00:06:18,540 --> 00:06:20,442 If you simply type git log, 77 00:06:20,442 --> 00:06:25,658 it'll display a lot more detailed information about all the commits, but 78 00:06:25,658 --> 00:06:30,652 this is sufficient enough for obtaining information that we require. 79 00:06:33,013 --> 00:06:40,820 Let's now come back to our editor here in Visual Studio Code. 80 00:06:40,820 --> 00:06:45,379 So I'm going to add more changes to my index.html file, so I will add, 81 00:06:54,307 --> 00:06:57,790 So I have changed my index.html file. 82 00:06:57,790 --> 00:07:02,453 Now let me add another folder under the git-test folder, so 83 00:07:02,453 --> 00:07:06,890 I will create a subfolder here named templates. 84 00:07:06,890 --> 00:07:09,344 And inside this templates folder, 85 00:07:09,344 --> 00:07:13,039 I'm going to create another file named test.html. 86 00:07:13,039 --> 00:07:17,798 This is just to show you how Git can commit entire folder 87 00:07:17,798 --> 00:07:21,120 hierarchy into its repository. 88 00:07:21,120 --> 00:07:24,734 So with test.html now there, 89 00:07:24,734 --> 00:07:29,321 I'm just going to copy everything from 90 00:07:29,321 --> 00:07:34,047 my index.html into my test.html, and 91 00:07:34,047 --> 00:07:41,422 save the changes Going back to the command line, 92 00:07:41,422 --> 00:07:46,187 let's now check out the status of our Git repository and this folder. 93 00:07:46,187 --> 00:07:51,079 So typing git status shows that the index.html file that we have 94 00:07:51,079 --> 00:07:55,971 already added earlier to the repository has now been modified, 95 00:07:55,971 --> 00:08:00,570 so there is a newer version of the index.html file. 96 00:08:00,570 --> 00:08:03,220 Also, it shows that there are some untracked 97 00:08:03,220 --> 00:08:05,530 files in this folder called templates. 98 00:08:06,620 --> 00:08:11,720 Let's add all these changes to our repository, to the staging area. 99 00:08:11,720 --> 00:08:16,350 So again, type git add., and 100 00:08:16,350 --> 00:08:21,620 then all these files will be added to the staging area. 101 00:08:21,620 --> 00:08:27,820 Again, checking out the status, you now see that the changes that have been 102 00:08:27,820 --> 00:08:32,850 added to the staging area, so all these files have been added to the staging area. 103 00:08:32,850 --> 00:08:37,735 Let's do one more commit, so I would say git commit -m, 104 00:08:41,526 --> 00:08:46,595 "Second commit", and then, let's check out the log. 105 00:08:50,794 --> 00:08:54,179 If you check out the log, you'll now see that there 106 00:08:54,179 --> 00:08:58,930 are two commits in my Git repository, the first and the second commit. 107 00:08:58,930 --> 00:09:02,826 And note that each one of them is given a different number there. 108 00:09:02,826 --> 00:09:09,700 If you want to see the full details of the log, you can type simply, git log. 109 00:09:09,700 --> 00:09:12,510 And then you will see more details in there 110 00:09:12,510 --> 00:09:15,095 than what you would be interested in. 111 00:09:15,095 --> 00:09:19,115 So notice that the one line commit 112 00:09:19,115 --> 00:09:24,405 only gives the first few characters of my commit number there. 113 00:09:24,405 --> 00:09:26,674 That is sufficient enough for us to operate with. 114 00:09:29,000 --> 00:09:34,006 Let me now go back again to my Visual Studio, and add one more, 115 00:09:43,821 --> 00:09:45,890 One more line to my index.html file. 116 00:09:47,140 --> 00:09:52,666 So now my index.html file has been modified, and let's save the changes. 117 00:09:55,066 --> 00:09:57,813 Going back to the command line, 118 00:09:57,813 --> 00:10:04,490 doing git status shows that the index.html file has been modified. 119 00:10:04,490 --> 00:10:08,640 So let's add this to the staging area, and 120 00:10:08,640 --> 00:10:14,382 then do a third commit, so let's say git add ., 121 00:10:14,382 --> 00:10:18,720 git status. 122 00:10:18,720 --> 00:10:22,700 Now you'll see that the index.html, the modified version, has been added. 123 00:10:22,700 --> 00:10:27,305 Now, we can say git commit, 124 00:10:31,164 --> 00:10:37,144 "Third commit", And do git log --oneline, 125 00:10:37,144 --> 00:10:43,818 and you'll see that there are three commits in our repository. 126 00:10:43,818 --> 00:10:47,625 So now our repository contains snapshots of three different points, 127 00:10:47,625 --> 00:10:51,234 at the end of the first commit, at the end of the second commit, and 128 00:10:51,234 --> 00:10:52,929 at the end of the third commit. 129 00:10:52,929 --> 00:10:56,297 Now we also can roll back changes, 130 00:10:56,297 --> 00:11:01,417 we can revert the repository to a previous version. 131 00:11:01,417 --> 00:11:04,366 We can pull out a file from an older commit and 132 00:11:04,366 --> 00:11:09,180 then replace the existing file in our directory from the older commit. 133 00:11:09,180 --> 00:11:13,604 So let's see how we can operate with these things by learning 134 00:11:13,604 --> 00:11:15,608 a couple of more commands. 135 00:11:15,608 --> 00:11:21,759 At this stage, our index.html file is in the current state, 136 00:11:21,759 --> 00:11:26,530 so you can notice that it has an h1 and two p's. 137 00:11:26,530 --> 00:11:29,365 Let's now look at the next Git command. 138 00:11:30,815 --> 00:11:36,185 The next Git command that we're going to learn about is git checkout. 139 00:11:36,185 --> 00:11:40,300 So this checkout command allows us to check out a file 140 00:11:40,300 --> 00:11:44,040 from a previous commit in our Git repository. 141 00:11:44,040 --> 00:11:47,709 So if we don't like the current file that we have in our folder, 142 00:11:47,709 --> 00:11:50,907 and we want to go back to a previous version of the file. 143 00:11:50,907 --> 00:11:54,782 We can always check out the file from a previous commit or 144 00:11:54,782 --> 00:12:00,230 from the current commit, and then continue to work with that file. 145 00:12:00,230 --> 00:12:07,190 So let's make use of this and see some further changes to our Git repository. 146 00:12:09,350 --> 00:12:14,705 Going back to our command line, we remember that, 147 00:12:14,705 --> 00:12:20,235 between the second and the third commit, I made changes to my index.html file. 148 00:12:20,235 --> 00:12:25,477 Suppose I want to revert back to the index.html file from my second commit. 149 00:12:25,477 --> 00:12:31,244 So then I can simply say, git checkout 900cfcf, 150 00:12:31,244 --> 00:12:35,045 so that is the commit identifier, 151 00:12:35,045 --> 00:12:40,980 the number that identifies that particular commit. 152 00:12:40,980 --> 00:12:46,117 And then I can say index.html, and what you would notice 153 00:12:46,117 --> 00:12:53,190 is that all the file will now be checked out into my current working directory. 154 00:12:55,721 --> 00:12:57,901 Going to my Visual Studio Code, 155 00:12:57,901 --> 00:13:03,340 you now notice that my index.html file has reverted to the previous version. 156 00:13:03,340 --> 00:13:07,928 So the change that I made before the third commit is now gone. 157 00:13:07,928 --> 00:13:16,482 So my index.html file has been restored to its state at the end of the second commit. 158 00:13:18,607 --> 00:13:22,936 Now at the command line, if I type git status, 159 00:13:22,936 --> 00:13:26,711 you notice that this index.html file, 160 00:13:26,711 --> 00:13:33,520 which has reverted to what it was at the end of the second commit. 161 00:13:33,520 --> 00:13:37,710 It has now already been staged, so using this git checkout 162 00:13:38,720 --> 00:13:43,670 will pull out an older version of the file and then replace what is in the current 163 00:13:43,670 --> 00:13:48,400 directory and then it will also check it into the staging area. 164 00:13:48,400 --> 00:13:53,400 So now, if I do that and then I realize that this is what I want, 165 00:13:53,400 --> 00:13:56,450 I can simply do another commit at this point. 166 00:13:56,450 --> 00:14:02,249 And then that file can be committed as the fourth commit, 167 00:14:02,249 --> 00:14:05,200 but suppose I don't like this. 168 00:14:05,200 --> 00:14:10,553 I want to revert back to the index.html file at 169 00:14:10,553 --> 00:14:17,704 the end of the third commit, then all I can do is say git reset, 170 00:14:20,178 --> 00:14:24,866 HEAD and index.html. 171 00:14:28,084 --> 00:14:32,404 So at this point, what happens is that the index.html, 172 00:14:32,404 --> 00:14:37,264 the modified version that I have checked out is still there, but 173 00:14:37,264 --> 00:14:41,137 this file has been unstaged from the staging area. 174 00:14:43,376 --> 00:14:48,440 If you go back and look at the index.html in your, 175 00:14:50,991 --> 00:14:56,094 Editor, it will still show the state at the end of the second commit 176 00:14:56,094 --> 00:15:01,255 because we had pulled out that file using checkout for that. 177 00:15:01,255 --> 00:15:06,900 Now if we want to revert it back to what it was at the end of the third commit, 178 00:15:06,900 --> 00:15:09,470 then we do one more checkout from the third commit. 179 00:15:10,540 --> 00:15:16,431 Going to our command window, type git status, and 180 00:15:16,431 --> 00:15:23,558 you would notice that the index.html is marked as modified. 181 00:15:23,558 --> 00:15:29,661 But it also shows this particular statement here, it says git checkout --, 182 00:15:29,661 --> 00:15:35,029 and the file name, to discard the changes in the working directory. 183 00:15:35,029 --> 00:15:38,334 So that's one way you can discard the changes that 184 00:15:38,334 --> 00:15:43,095 are made to a particular file corresponding to the previous commit. 185 00:15:43,095 --> 00:15:46,565 So let me restore this index.html back to what it was 186 00:15:46,565 --> 00:15:47,653 at the end of the third commit. 187 00:15:47,653 --> 00:15:54,315 So to do that, I will simply say git checkout -- 188 00:15:54,315 --> 00:15:58,712 index.html, and then if I do, 189 00:16:01,503 --> 00:16:05,815 Git status, it shows that my directory is clean, and basically my 190 00:16:05,815 --> 00:16:10,520 directory has been restored to the state of the end of the third comment. 191 00:16:12,370 --> 00:16:16,909 Going to the file in my Visual Studio Code, I see that the file has been 192 00:16:16,909 --> 00:16:20,767 restored back to what it was at the end of the third commit. 193 00:16:20,767 --> 00:16:25,251 So if you have made changes to a file after a commit and you want to just 194 00:16:25,251 --> 00:16:30,632 discard those changes, you can simply checkout the file from the last commit. 195 00:16:30,632 --> 00:16:35,338 And then all your changes that you've done after the last commit will be discarded at 196 00:16:35,338 --> 00:16:36,144 this part.. 197 00:16:36,144 --> 00:16:40,304 So these are some basic commands that are very useful for 198 00:16:40,304 --> 00:16:42,958 you as you go through the courses and 199 00:16:42,958 --> 00:16:48,821 the specialization because you may want to commit at the end of each exercise. 200 00:16:48,821 --> 00:16:51,617 And as you proceed forward, 201 00:16:51,617 --> 00:16:56,744 you would still have a committed version of the state 202 00:16:56,744 --> 00:17:01,790 of your folder at the end of the previous exercise. 203 00:17:01,790 --> 00:17:06,249 So that way if you are carrying out a new exercise and you discover that you've 204 00:17:06,249 --> 00:17:10,032 made mistakes and you want to revert back to the previous commit. 205 00:17:10,032 --> 00:17:14,832 You'll always have a way of doing that using the commands 206 00:17:14,832 --> 00:17:18,010 that we have just learned. 207 00:17:18,010 --> 00:17:24,430 So with this basic understanding of these few Git commands, 208 00:17:24,430 --> 00:17:29,427 we would be able to proceed forward with understanding and 209 00:17:29,427 --> 00:17:33,570 using Git in the courses of this specialization. 210 00:17:35,560 --> 00:17:41,434 So now, we have reviewed the git reset for a specific file or git reset in general. 211 00:17:41,434 --> 00:17:47,970 If you simply type get reset, it'll restore you back to the last commit. 212 00:17:47,970 --> 00:17:51,360 So it will reset the staging area to the last commit 213 00:17:51,360 --> 00:17:55,270 without disturbing the changes that you've done to your working directory. 214 00:17:55,270 --> 00:17:59,270 So once you reset, then you can checkout the previous 215 00:17:59,270 --> 00:18:02,140 version of the file that you have committed in the previous commit. 216 00:18:02,140 --> 00:18:05,940 So this way you can restore your folder back to where you were 217 00:18:07,440 --> 00:18:10,450 at the starting point of the previous commit. 218 00:18:10,450 --> 00:18:16,037 So sometimes when you are going through an exercise and you realize you made mistake, 219 00:18:16,037 --> 00:18:20,082 you always have a way of reverting back to a previous version. 220 00:18:20,082 --> 00:18:25,081 So with these commands I think you're all set to go ahead to use 221 00:18:25,081 --> 00:18:28,651 Git in the courses of this specialization. 222 00:18:30,865 --> 00:18:33,694 So at the end of this exercise, did you Git it? 223 00:18:33,694 --> 00:18:37,459 [MUSIC]