Git/C2/The-git-checkout-command/English-timed

From Script | Spoken-Tutorial
Revision as of 10:52, 28 March 2017 by PoojaMoolya (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
Time
Narration
00:01 Welcome to the spoken tutorial on git checkout command.
00:06 In this tutorial, we will learn how to: * add multiple files to Git repository
00:12 Remove a file from Git repository
00:16 Restore the removed file
00:18 Discard the changes made to a file and
00:21 Revert to an earlier revision.
00:25 For this tutorial, I am using: Ubuntu Linux 14.04,
00:31 Git 2.3.2 and gedit Text Editor.
00:36 You can use any editor of your choice.
00:40 To follow this tutorial, you must have knowledge of running Linux commands on Terminal.
00:47 If not, for relevant Linux tutorials, please visit our website.
00:52 Now, let us see how to add multiple files to the Git repository.
00:58 Press Ctrl+Alt+T to open the terminal.
01:02 We will go into our Git repository "mywebpage" which we created earlier.
01:09 Type: cd space mywebpage and press Enter.
01:14 I will continue to use html files for demonstration.
01:19 You may use any file type of your choice.
01:23 We will create 2 html files now.
01:27 So, type: gedit space mystory.html space mynovel.html space ampersand.
01:37 We use the & (ampersand) to free up the prompt. Press' Enter.
01:43 I will copy and paste some code into these files, from my Writer document, which I had saved earlier.
01:50 Let us save these fies.
01:53 In the terminal, first check the Git status by typing git space status and press Enter.
02:03 It shows two untracked files.
02:06 We will now add the untracked files for tracking.
02:10 Type: git space add space dot and press Enter.
02:17 The git add dot command will add all the untracked files to the staging area.
02:23 Hence, the two files "mystory.html" and "mynovel.html" are added to the staging area.
02:32 Let’s check the Git status once again by typing git space status and press Enter.
02:40 Now, we can see that both our files have been added to the staging area of the Git repository.
02:47 Let us switch back to our files mystory.html and mynovel.html.
02:54 Now, we will add a few more lines of code to both these files.
03:00 Like before, I will copy-paste from my Writer document.
03:05 Once again save and close the files.
03:08 Let’s check the Git status by typing git space status and press Enter.
03:16 It shows “Changes not staged for commit” and “modified: mynovel.html" and "mystory.html”.
03:26 This means that the changes we made, have not been added to the staging area.
03:32 Let us now commit our work at this point.
03:36 So, type: git space commit space hyphen a space hyphen m space within double quotes “Added two files” and press Enter.
03:50 Note that we didn't add the modified files to the staging area before committing them and
03:57 the editor also didn't open up for committing message as we saw in earlier tutorial.
04:03 This is because, here we have used hyphena and hyphen m flags.
04:10 So, what are these flags for?
04:13 Switch back to our slides.
04:15 Hyphen 'a' flag is used to add all the modified files to the staging area.
04:21 When we use hyphen a flag, we don’t need git add command separately to add the modified files to the staging area.
04:30 Hyphen m flag is used to give commit message in the command line itself.
04:36 We can use the flags hyphen a and hyphen m as hyphen am.
04:42 Switch back to the terminal.
04:45 Check the Git log by typing git space log and press Enter.
04:52 You can see the list of commits.
04:54 Note that the latest commits are listed first
04:58 which means the commits are listed in chronological order.
05:03 In case, you have added a wrong file to the Git repository, it can be easily removed.
05:10 Say, for example, I want to remove the file mypage.html.
05:16 Type: git space rm space hyphen hyphen cached space mypage dot html and press Enter.
05:26 This command will remove the file mypage.html from the staging area.
05:32 We will check the Git status now by typing git space status and press Enter.
05:40 It says that the file mypage.html is untracked.
05:45 Now, we can delete the file from file system by typing
05:49 rm space mypage dot html and press Enter.
05:55 This command would completely remove the file from mywebpage folder.
06:00 Now, we will check whether the file has been removed from the Git repository.
06:06 So, type: git space status and press Enter.
06:12 It shows the message “deleted: mypage.html”.
06:16 Now, list the files by typing "ls" and press Enter.
06:21 Here, we cannot see the file mypage.html anymore as it has been deleted.
06:28 At this point, let’s freeze our code.
06:32 To commit, type: git space commit space hyphen am space within double quotes “Deleted mypage.html” and press Enter.
06:45 Let’s see the Git log by typing git space log and press Enter.
06:51 Press q key on your keyboard to exit.
06:55 Here, we can find the latest commit by reading the commit message.
06:59 Now, suppose that we have deleted mypage.html by mistake and now we want to restore it back.
07:08 What can we do? We can restore the deleted file from the previous commits.
07:13 Let’s restore our file from the second commit, which has the commit message “Added two files”.
07:20 Select the first five digits of the second commit hash
07:24 and press Ctrl + Shift + C keys to copy them.
07:28 The first five digits are sufficient.
07:31 But you can copy more than five digits also, if you wish to.
07:36 Type: git space checkout space and press Ctrl + Shift + V keys to paste the commit hash.
07:45 Now, type the file name "mypage.html" and press Enter.
07:51 Check the Git status by typing git space status and press Enter.
07:58 Now, you can see the file mypage.html.
08:02 Let us commit our work at this point.
08:05 Note that it is very important to commit our work whenever we add or delete any file.
08:12 Type: git space commit space hyphen am space “Restored mypage.html” and press Enter.
08:22 Now, list the files by typing ls and press Enter.
08:28 We can see that our file mypage.html is restored.
08:33 Next, we will see how to discard the changes made to a file.
08:38 Open the files by typing gedit space mypage.html space mystory.html space ampersand and press Enter.
08:50 We will do some modifications in mypage.html and mystory.html.
08:58 Let us add and delete some lines in both the files.
09:03 Then save and close the files.
09:06 In certain situations, we may not want to continue with these changes.
09:11 That means, we want to go back to the previous stage of our work.
09:16 Let us learn how to do it.
09:19 First, we will check the Git status by typing git space status and press Enter.
09:27 It says that some files have been modified.
09:30 Now, type: git space checkout space dot and press Enter.
09:37 This command will delete the latest changes of our work.
09:41 Check the Git status by typing git space status and press Enter.
09:48 It says “nothing to commit”.
09:51 Let us check the files to see whether the changes are still there or not.
09:57 Type: gedit space mypage.html space mystory.html & and press Enter.
10:07 We can see that our modifications have been discarded. Close the files.
10:13 Now, let us check the Git log by typing git space log and press Enter.
10:20 It shows list of commits.
10:23 Press down arrow key to see more.
10:26 Press q key on your keyboard to exit.
10:30 If you want to see the commits list in one line, type: git space log space hyphen hyphen oneline and press Enter.
10:42 Here, you can see the commits list with their commit hash and commit messages in one line.
10:48 How can we go to a previous revision of our work?
10:53 Currently we have four commits in our repository
10:56 which means, we have four revisions of our work.
11:01 Say, we want to go back to the “Initial commit” stage.
11:05 So, type: git space checkout space, then copy and paste the commit hash of the Initial commit and press Enter.
11:15 List the files by typing ls and press Enter.
11:19 We can see only one file mypage.html here, because in this stage, we had only this file.
11:28 Now, check the Git log by typing git space log and press Enter.
11:34 We can see the first commit only i.e. the Initial commit.
11:39 To return back to the current revision, type: git space checkout space master and press Enter.
11:48 We will learn more about the term master in future tutorials.
11:53 Let’s check the Git log once again by typing
11:57 git space log space hyphen hyphen oneline and press Enter.
12:03 Now you can see all four commits. So, we are now at the latest stage.
12:10 In this manner, we can go back to any stage of our work.
12:14 There is another way to go to the old revision.
12:18 Type: git space reset space hyphen hyphen hard.
12:23 Then copy and paste the commit hash of the Initial commit and press Enter.
12:29 Check the Git log by typing git space log and press Enter.
12:35 It shows that we are now at the Initial commit stage.
12:39 Now, let’s try to go back to the latest revision.
12:43 Like before, type: git space checkout space master and press Enter.
12:51 We are unable to go back to the latest revision.
12:55 Instead, we get a message: “Already on 'master'”.
12:58 It means this is our latest revision.
13:02 So, note, once we use the command git reset hyphen hyphen hard, we can't go back to the latest stage.
13:11 So, we should be very careful with this command.
13:15 With this, we come to the end of this tutorial.
13:18 Let us summarize. In this tutorial, we have learnt how to: *Add multiple files to Git repository
13:27 Remove a file from Git repository. * Restore the removed file
13:32 Discard the changes made to a file and * Revert to an earlier revision.
13:39 As an assignment- Go to your Git repository which you created in the previous tutorial assignment.
13:46 Do some modifications in your text file.
13:49 Commit the changes.
13:52 Try to revert to your old revision.
13:55 Again do some modifications in your text file and try to discard the changes.
14:02 The video at the following link summarizes the Spoken Tutorial project; please download and watch it.
14:11 The Spoken Tutorial Project team conducts workshops and gives certificates to those who pass online tests.
14:18 For more details, please write to us.
14:22 Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.
14:29 More information on this mission is available at the following link.
14:34 This is Priya from IIT Bombay. Thanks for joining.

Contributors and Content Editors

PoojaMoolya, Sandhya.np14