WEBVTT 0 00:00.140 --> 00:05.120 Now, in the last lesson, we spoke about some of the more basic variants of version control. 1 00:05.150 --> 00:09.110 In this lesson, I want to talk about Branches and Branching. 2 00:09.140 --> 00:11.580 Now let's start off with a simple example, 3 00:11.600 --> 00:14.990 say if we had Version 1 and 2, 4 00:15.020 --> 00:18.800 so two commits that were made to our local repository, 5 00:18.800 --> 00:25.610 and at this point, we realize that we want to maybe try out something different, maybe build a new feature, 6 00:25.610 --> 00:28.730 or just to mess around with a new idea or concept. 7 00:28.760 --> 00:35.690 What we can do is instead of continuing to commit to the main branch that you see here, we can also 8 00:35.690 --> 00:39.470 create a side branch. After the second commit, 9 00:39.500 --> 00:46.880 we create a new branch and we start committing to this new branch or this experimental branch. 10 00:46.910 --> 00:50.150 We add some features and we write some code. 11 00:50.330 --> 00:56.810 Simultaneously, we can continue working on the main branch, putting out all those essential updates 12 00:56.810 --> 01:01.860 or bits of code that are maintaining our main project, 13 01:01.860 --> 01:08.520 but at the same time we can continue to update and work on this experimental branch trying things out 14 01:08.520 --> 01:11.840 and committing our experiments to this experimental branch. 15 01:11.850 --> 01:18.610 So now we have two branches that are parallel to each other and they can be developed simultaneously. 16 01:18.630 --> 01:24.900 If at some point in the future that we decide that that experiment was really fruitful, and the feature 17 01:24.900 --> 01:30.930 that we built in it was really, really great and we'd like to merge it back to the main branch or 18 01:30.930 --> 01:37.350 to the main project, then that can be done really easily as well by simply placing a merge request 19 01:37.350 --> 01:44.370 in. And we can bring all of those changes that we experimented with, that we messed around with, back to 20 01:44.370 --> 01:49.200 the main project and check to see if there's any conflict with the main branch code 21 01:49.200 --> 01:55.740 and if not, or if after a little bit of editing, then we can bring all of those changes into the main 22 01:55.740 --> 02:03.870 working branch. And then we can continue working from here onto to the next commit or we can make more 23 02:03.870 --> 02:04.620 branches. 24 02:04.620 --> 02:10.650 And very often what you see in practice is that there'll be multiple branches being worked on at the 25 02:10.650 --> 02:13.350 same time for any given large project. 26 02:13.350 --> 02:19.950 And the reason is because sometimes you're developing new features, sometimes you are fixing bugs and 27 02:19.950 --> 02:25.350 all of these things may break your main project, so you don't want to do it on the main branch. 28 02:25.350 --> 02:28.230 You only want to put it onto the main branch 29 02:28.230 --> 02:35.130 once you know that everything is working fine, and then you can bring your code back to the working copy 30 02:35.130 --> 02:37.410 ready for shipment and deployment. 31 02:37.530 --> 02:41.370 Let's take a look at how this would work in reality. 32 02:41.400 --> 02:49.890 Now let's say we navigate back to our Story directory, and inside here we've still got our previous 33 02:49.890 --> 02:53.430 three chapters and they are under version control. 34 02:53.430 --> 02:59.880 So if we just have a look at "git log", you can see that this is currently the most recent commit and 35 02:59.880 --> 03:02.580 it's also mirrored in our remote. 36 03:03.470 --> 03:06.260 Let's try and do this locally first. 37 03:06.410 --> 03:14.120 If I decided that I want to create a new branch, you can simply just write "git branch" and specify the 38 03:14.120 --> 03:16.050 name of your new branch. 39 03:16.070 --> 03:25.580 I'm going to add a space-related plot to my story, so let's call our branch, "alien-plot." 40 03:27.000 --> 03:27.840 Hit Enter. 41 03:27.840 --> 03:34.710 And now you can check out what branches you have by just writing "git branch" without the name and you 42 03:34.710 --> 03:40.440 can see that you've got one branch called, alien-plot and another one called main, and the asterisks (*) 43 03:40.440 --> 03:43.470 shows you which branch you are currently on. 44 03:43.470 --> 03:45.330 So we're currently on the main branch. 45 03:45.360 --> 03:50.940 We can switch to the alien-plot by simply writing "git checkout 46 03:51.780 --> 03:53.700 alien-plot". 47 03:56.580 --> 03:57.110 Okay. 48 03:57.120 --> 04:01.200 As it says, we have now switched to the branch called, alien-plot. 49 04:01.350 --> 04:07.290 Now, it is inside this branch that I'm going to make some changes to my chapters. 50 04:07.470 --> 04:14.730 Now I'm going to make some completely nonsensical modification to my files. 51 04:14.730 --> 04:16.680 So let's change chapter 1. 52 04:16.680 --> 04:19.860 Let's change chapter2. 53 04:26.520 --> 04:27.690 Okay. 54 04:27.870 --> 04:28.540 There we go. 55 04:28.560 --> 04:34.770 Okay, so we've made some modifications to chapter1 and chapter2, and we've decided to change some 56 04:34.770 --> 04:41.070 of the pre-existing written text to integrate a space-themed or alien-themed plot. 57 04:42.030 --> 04:44.220 Let's go ahead and commit that. 58 04:44.220 --> 04:55.500 So remember, we have to do "git add ." and then "git commit -m..." and our message is going to be "modify 59 04:56.010 --> 04:57.390 chapter 1 60 04:58.830 --> 05:04.950 and 2 to have alien theme". 61 05:06.490 --> 05:10.870 Okay, now hit Enter and we've made our commits. 62 05:11.020 --> 05:18.790 Now if we do a "git log", we can see that we have two commits made on the main branch and we have one 63 05:18.790 --> 05:21.970 commit made on the alien plot-branch. 64 05:22.120 --> 05:25.890 So now let's say that we go back onto our main branch. 65 05:25.900 --> 05:32.170 Whenever you're confused where you are, you can always do a "git branch" to check and see where the asterisks 66 05:32.170 --> 05:32.410 is. 67 05:32.410 --> 05:35.200 And the asterisks is obviously where you are. 68 05:35.230 --> 05:43.810 So let's do a "git checkout main" to go back to the main branch. So you can see that our main branch is 69 05:43.810 --> 05:44.740 unchanged 70 05:44.740 --> 05:48.790 with respect to the space or alien plot that we did just now. 71 05:48.790 --> 05:51.040 Nothing has changed over here. 72 05:51.040 --> 05:54.700 So while on the main branch, I'm going to create a new file, 73 05:54.700 --> 05:56.440 I'm going to call it chapter4.txt. 74 05:58.040 --> 06:03.690 And inside chapter four, 75 06:03.710 --> 06:05.300 let's add something. 76 06:09.640 --> 06:10.090 Okay. 77 06:10.090 --> 06:11.920 And hit, Enter and Save. 78 06:11.950 --> 06:13.600 By the way, I have no idea what I'm typing. 79 06:13.600 --> 06:18.600 I'm now making up and destroying, probably in the process a masterpiece, but it's okay. 80 06:18.610 --> 06:25.060 So we now have a chapter4 on our main branch and I'm going to go ahead and do a "git add ." and "git 81 06:25.060 --> 06:26.110 commit". 82 06:26.830 --> 06:32.230 Now there's ways of combining add and commit together in the same command, but I think if you're new 83 06:32.230 --> 06:36.070 to git, it's always good to really know in your head exactly what's going on. 84 06:36.070 --> 06:39.370 So I recommend actually separating those two bits out. 85 06:39.400 --> 06:42.340 Let's go ahead and give it a commit message. 86 06:42.520 --> 06:45.130 "add chapter 4." 87 06:45.970 --> 06:47.760 Okay, so "git log". 88 06:47.770 --> 06:48.400 Let's see, 89 06:48.400 --> 06:49.240 what have we got? 90 06:49.270 --> 06:53.470 We are currently only looking at the main branch and we have three commits. 91 06:53.500 --> 06:57.250 This is the position of our remote. 92 06:57.250 --> 07:02.650 So on our GitHub repository, this was the latest commit that it could see. 93 07:02.650 --> 07:08.410 But on our local git repository, this is in fact the latest commit, the one that we just made where 94 07:08.410 --> 07:09.920 we added chapter4. 95 07:09.920 --> 07:16.640 And you can see that if I switch between the branches, say, if I go over to alien-plot branch and hit 96 07:16.640 --> 07:22.120 Enter, you can see that our local files actually changed as I switched branches. 97 07:22.130 --> 07:29.030 Let's just say that I'm quite happy with the changes that I've made in terms of my alien-plot addition 98 07:29.030 --> 07:33.920 and I would like to merge these changes back into my main branch. 99 07:33.920 --> 07:37.550 So I've done a little bit of experimentation on a separate branch, 100 07:37.550 --> 07:42.050 I've, you know, messed with a few things and I think it was a great experiment. 101 07:42.050 --> 07:46.130 So I'm going to put it back into our main branch. 102 07:46.220 --> 07:50.870 In order to do that, what you have to do is go back to the main branch. 103 07:50.870 --> 07:59.000 So "git checkout main" and while we're on the main branch we're going to merge the changes inside the 104 07:59.000 --> 08:00.260 alien-plot branch. 105 08:00.260 --> 08:09.890 So we use the command "git merge" and we're going to specify the branch name which was, "alien-plot" hit 106 08:09.890 --> 08:10.400 Enter. 107 08:10.400 --> 08:16.550 And this opens up Vim, which is a text editor, and this allows you to add a merge message if you wish. 108 08:16.550 --> 08:20.810 And alternatively, as we're going to do here, we're just going to leave it empty and you're going 109 08:20.810 --> 08:24.500 to write, ":q!" to save and quit. 110 08:25.380 --> 08:31.440 And you can see now I've actually absorbed those changes from the alien plot. 111 08:31.530 --> 08:37.800 And you can see that because if I do "git branch", I am on the main branch. 112 08:37.800 --> 08:39.600 The alien plot branch still exists 113 08:39.600 --> 08:45.480 by the way. If you have a look at "git log", you can see that I've got some of the previous commits, 114 08:45.480 --> 08:51.180 but I've also got this merge branch alien-plot which was my most recent commit. 115 08:51.210 --> 09:00.960 Now, at this point let's do a "git push" to our "origin main" and remember to add the "-u" flag. 116 09:02.090 --> 09:03.110 That's completed. 117 09:03.110 --> 09:05.110 And let's check it out online. 118 09:05.120 --> 09:10.760 If we go over to our story repository, you can see that there's now five commits. 119 09:11.000 --> 09:13.010 We modified Chapter 1 and 2. 120 09:13.040 --> 09:17.150 We added chapter 4 and we merged the alien-plot branch. 121 09:17.150 --> 09:24.290 So if you go into insights and go to Network now, if I zoom in on this Network graph, then you can 122 09:24.290 --> 09:27.590 see this is the process that we've gone through. 123 09:27.770 --> 09:32.030 This is the main branch where we did chapter 1 and chapter 2 124 09:32.030 --> 09:39.200 and then at this point, after I created chapter 2 and 3, I created a new branch. 125 09:39.200 --> 09:45.380 And while inside this branch I made a commit that modified chapter 1 and 2 to have an alien theme. 126 09:45.380 --> 09:51.350 And then on the main branch, I continued developing the main branch, adding a chapter 4, 127 09:51.350 --> 10:00.800 but subsequently, I realized that I did a great job adding alien themes to our storyline and I decided 128 10:00.800 --> 10:04.410 to merge it back into the main branch. 129 10:04.410 --> 10:08.850 This is basically a graphical representation of what's been going on. 130 10:09.000 --> 10:12.750 So that was us creating a branch and merging it. 131 10:12.780 --> 10:19.590 Now, why don't you go ahead and have a go and create your own repository both locally as well as on GitHub? 132 10:19.590 --> 10:27.420 And, you know, write a story or write a poem, anything you like, and check out the amazingness that 133 10:27.420 --> 10:29.640 is Branching using git.