From 42035aa84ae5ad49ea7d2f5a3a3ee99bf606823a Mon Sep 17 00:00:00 2001 From: Julia Evans Date: Fri, 25 Sep 2026 11:43:41 -0400 Subject: [PATCH 1/2] doc: remove gittutorial The next commit replaces it with a new tutorial. Do this as a remove/add instead of just replacing the file in a single commit to make the patches easier to read on the mailing list, since the existing content isn't being reused. Signed-off-by: Julia Evans --- Documentation/gittutorial.adoc | 671 --------------------------------- 1 file changed, 671 deletions(-) delete mode 100644 Documentation/gittutorial.adoc diff --git a/Documentation/gittutorial.adoc b/Documentation/gittutorial.adoc deleted file mode 100644 index 03120ba19105e8..00000000000000 --- a/Documentation/gittutorial.adoc +++ /dev/null @@ -1,671 +0,0 @@ -gittutorial(7) -============== - -NAME ----- -gittutorial - A tutorial introduction to Git - -DESCRIPTION ------------ - -This tutorial explains how to import a new project into Git, make -changes to it, and share changes with other developers. - -If you are instead primarily interested in using Git to fetch a project, -for example, to test the latest version, you may prefer to start with -the first two chapters of link:user-manual.html[The Git User's Manual]. - -First, note that you can get documentation for a command such as -`git log --graph` with: - ------------------------------------------------- -$ man git-log ------------------------------------------------- - -or: - ------------------------------------------------- -$ git help log ------------------------------------------------- - -With the latter, you can use the manual viewer of your choice; see -linkgit:git-help[1] for more information. - -It is a good idea to introduce yourself to Git with your name and -public email address before doing any operation. The easiest -way to do so is: - ------------------------------------------------- -$ git config --global user.name "Your Name Comes Here" -$ git config --global user.email you@yourdomain.example.com ------------------------------------------------- - - -Importing a new project ------------------------ - -Assume you have a tarball `project.tar.gz` with your initial work. You -can place it under Git revision control as follows. - ------------------------------------------------- -$ tar xzf project.tar.gz -$ cd project -$ git init ------------------------------------------------- - -Git will reply - ------------------------------------------------- -Initialized empty Git repository in .git/ ------------------------------------------------- - -You've now initialized the working directory--you may notice a new -directory created, named `.git`. - -Next, tell Git to take a snapshot of the contents of all files under the -current directory (note the `.`), with `git add`: - ------------------------------------------------- -$ git add . ------------------------------------------------- - -This snapshot is now stored in a temporary staging area which Git calls -the "index". You can permanently store the contents of the index in the -repository with `git commit`: - ------------------------------------------------- -$ git commit ------------------------------------------------- - -This will prompt you for a commit message. You've now stored the first -version of your project in Git. - -Making changes --------------- - -Modify some files, then add their updated contents to the index: - ------------------------------------------------- -$ git add file1 file2 file3 ------------------------------------------------- - -You are now ready to commit. You can see what is about to be committed -using `git diff` with the `--cached` option: - ------------------------------------------------- -$ git diff --cached ------------------------------------------------- - -(Without `--cached`, `git diff` will show you any changes that -you've made but not yet added to the index.) You can also get a brief -summary of the situation with `git status`: - ------------------------------------------------- -$ git status -On branch master -Changes to be committed: - (use "git restore --staged ..." to unstage) - - modified: file1 - modified: file2 - modified: file3 - ------------------------------------------------- - -If you need to make any further adjustments, do so now, and then add any -newly modified content to the index. Finally, commit your changes with: - ------------------------------------------------- -$ git commit ------------------------------------------------- - -This will again prompt you for a message describing the change, and then -record a new version of the project. - -Alternatively, instead of running `git add` beforehand, you can use - ------------------------------------------------- -$ git commit -a ------------------------------------------------- - -which will automatically notice any modified (but not new) files, add -them to the index, and commit, all in one step. - -A note on commit messages: Though not required, it's a good idea to -begin the commit message with a single short (no more than 50 -characters) line summarizing the change, followed by a blank line and -then a more thorough description. The text up to the first blank line in -a commit message is treated as the commit title, and that title is used -throughout Git. For example, linkgit:git-format-patch[1] turns a -commit into email, and it uses the title on the Subject line and the -rest of the commit in the body. - -Git tracks content not files ----------------------------- - -Many revision control systems provide an `add` command that tells the -system to start tracking changes to a new file. Git's `add` command -does something simpler and more powerful: `git add` is used both for new -and newly modified files, and in both cases it takes a snapshot of the -given files and stages that content in the index, ready for inclusion in -the next commit. - -Viewing project history ------------------------ - -At any point you can view the history of your changes using - ------------------------------------------------- -$ git log ------------------------------------------------- - -If you also want to see complete diffs at each step, use - ------------------------------------------------- -$ git log -p ------------------------------------------------- - -Often the overview of the change is useful to get a feel of -each step - ------------------------------------------------- -$ git log --stat --summary ------------------------------------------------- - -Managing branches ------------------ - -A single Git repository can maintain multiple branches of -development. To create a new branch named `experimental`, use - ------------------------------------------------- -$ git branch experimental ------------------------------------------------- - -If you now run - ------------------------------------------------- -$ git branch ------------------------------------------------- - -you'll get a list of all existing branches: - ------------------------------------------------- - experimental -* master ------------------------------------------------- - -The `experimental` branch is the one you just created, and the -`master` branch is a default branch that was created for you -automatically. The asterisk marks the branch you are currently on; -type - ------------------------------------------------- -$ git switch experimental ------------------------------------------------- - -to switch to the `experimental` branch. Now edit a file, commit the -change, and switch back to the `master` branch: - ------------------------------------------------- -(edit file) -$ git commit -a -$ git switch master ------------------------------------------------- - -Check that the change you made is no longer visible, since it was -made on the `experimental` branch and you're back on the `master` branch. - -You can make a different change on the `master` branch: - ------------------------------------------------- -(edit file) -$ git commit -a ------------------------------------------------- - -at this point the two branches have diverged, with different changes -made in each. To merge the changes made in `experimental` into `master`, run - ------------------------------------------------- -$ git merge experimental ------------------------------------------------- - -If the changes don't conflict, you're done. If there are conflicts, -markers will be left in the problematic files showing the conflict; - ------------------------------------------------- -$ git diff ------------------------------------------------- - -will show this. Once you've edited the files to resolve the -conflicts, - ------------------------------------------------- -$ git commit -a ------------------------------------------------- - -will commit the result of the merge. Finally, - ------------------------------------------------- -$ gitk ------------------------------------------------- - -will show a nice graphical representation of the resulting history. - -At this point you could delete the `experimental` branch with - ------------------------------------------------- -$ git branch -d experimental ------------------------------------------------- - -This command ensures that the changes in the `experimental` branch are -already in the current branch. - -If you develop on a branch `crazy-idea`, then regret it, you can always -delete the branch with - -------------------------------------- -$ git branch -D crazy-idea -------------------------------------- - -Branches are cheap and easy, so this is a good way to try something -out. - -Using Git for collaboration ---------------------------- - -Suppose that Alice has started a new project with a Git repository in -`/home/alice/project`, and that Bob, who has a home directory on the -same machine, wants to contribute. - -Bob begins with: - ------------------------------------------------- -bob$ git clone /home/alice/project myrepo ------------------------------------------------- - -This creates a new directory `myrepo` containing a clone of Alice's -repository. The clone is on an equal footing with the original -project, possessing its own copy of the original project's history. - -Bob then makes some changes and commits them: - ------------------------------------------------- -(edit files) -bob$ git commit -a -(repeat as necessary) ------------------------------------------------- - -When he's ready, he tells Alice to pull changes from the repository -at `/home/bob/myrepo`. She does this with: - ------------------------------------------------- -alice$ cd /home/alice/project -alice$ git pull /home/bob/myrepo master ------------------------------------------------- - -This merges the changes from Bob's `master` branch into Alice's -current branch. If Alice has made her own changes in the meantime, -then she may need to manually fix any conflicts. - -The `pull` command thus performs two operations: it fetches changes -from a remote branch, then merges them into the current branch. - -Note that in general, Alice would want her local changes committed before -initiating this `pull`. If Bob's work conflicts with what Alice did since -their histories forked, Alice will use her working tree and the index to -resolve conflicts, and existing local changes will interfere with the -conflict resolution process (Git will still perform the fetch but will -refuse to merge -- Alice will have to get rid of her local changes in -some way and pull again when this happens). - -Alice can peek at what Bob did without merging first, using the `fetch` -command; this allows Alice to inspect what Bob did, using a special -symbol `FETCH_HEAD`, in order to determine if he has anything worth -pulling, like this: - ------------------------------------------------- -alice$ git fetch /home/bob/myrepo master -alice$ git log -p HEAD..FETCH_HEAD ------------------------------------------------- - -This operation is safe even if Alice has uncommitted local changes. -The range notation `HEAD..FETCH_HEAD` means "show everything that is reachable -from the `FETCH_HEAD` but exclude anything that is reachable from `HEAD`". -Alice already knows everything that leads to her current state (`HEAD`), -and reviews what Bob has in his state (`FETCH_HEAD`) that she has not -seen with this command. - -If Alice wants to visualize what Bob did since their histories forked -she can issue the following command: - ------------------------------------------------- -$ gitk HEAD..FETCH_HEAD ------------------------------------------------- - -This uses the same two-dot range notation we saw earlier with `git log`. - -Alice may want to view what both of them did since they forked. -She can use three-dot form instead of the two-dot form: - ------------------------------------------------- -$ gitk HEAD...FETCH_HEAD ------------------------------------------------- - -This means "show everything that is reachable from either one, but -exclude anything that is reachable from both of them". - -Please note that these range notations can be used with both `gitk` -and `git log`. - -After inspecting what Bob did, if there is nothing urgent, Alice may -decide to continue working without pulling from Bob. If Bob's history -does have something Alice would immediately need, Alice may choose to -stash her work-in-progress first, do a `pull`, and then finally unstash -her work-in-progress on top of the resulting history. - -When you are working in a small closely knit group, it is not -unusual to interact with the same repository over and over -again. By defining 'remote' repository shorthand, you can make -it easier: - ------------------------------------------------- -alice$ git remote add bob /home/bob/myrepo ------------------------------------------------- - -With this, Alice can perform the first part of the `pull` operation -alone using the `git fetch` command without merging them with her own -branch, using: - -------------------------------------- -alice$ git fetch bob -------------------------------------- - -Unlike the longhand form, when Alice fetches from Bob using a -remote repository shorthand set up with `git remote`, what was -fetched is stored in a remote-tracking branch, in this case -`bob/master`. So after this: - -------------------------------------- -alice$ git log -p master..bob/master -------------------------------------- - -shows a list of all the changes that Bob made since he branched from -Alice's `master` branch. - -After examining those changes, Alice -could merge the changes into her `master` branch: - -------------------------------------- -alice$ git merge bob/master -------------------------------------- - -This `merge` can also be done by 'pulling from her own remote-tracking -branch', like this: - -------------------------------------- -alice$ git pull . remotes/bob/master -------------------------------------- - -Note that git pull always merges into the current branch, -regardless of what else is given on the command line. - -Later, Bob can update his repo with Alice's latest changes using - -------------------------------------- -bob$ git pull -------------------------------------- - -Note that he doesn't need to give the path to Alice's repository; -when Bob cloned Alice's repository, Git stored the location of her -repository in the repository configuration, and that location is -used for pulls: - -------------------------------------- -bob$ git config --get remote.origin.url -/home/alice/project -------------------------------------- - -(The complete configuration created by `git clone` is visible using -`git config list`, and the linkgit:git-config[1] man page -explains the meaning of each option.) - -Git also keeps a pristine copy of Alice's `master` branch under the -name `origin/master`: - -------------------------------------- -bob$ git branch -r - origin/master -------------------------------------- - -If Bob later decides to work from a different host, he can still -perform clones and pulls using the ssh protocol: - -------------------------------------- -bob$ git clone alice.org:/home/alice/project myrepo -------------------------------------- - -Alternatively, Git has a native protocol, or can use http; -see linkgit:git-pull[1] for details. - -Git can also be used in a CVS-like mode, with a central repository -that various users push changes to; see linkgit:git-push[1] and -linkgit:gitcvs-migration[7]. - -Exploring history ------------------ - -Git history is represented as a series of interrelated commits. We -have already seen that the `git log` command can list those commits. -Note that first line of each `git log` entry also gives a name for the -commit: - -------------------------------------- -$ git log -commit c82a22c39cbc32576f64f5c6b3f24b99ea8149c7 -Author: Junio C Hamano -Date: Tue May 16 17:18:22 2006 -0700 - - merge-base: Clarify the comments on post processing. -------------------------------------- - -We can give this name to `git show` to see the details about this -commit. - -------------------------------------- -$ git show c82a22c39cbc32576f64f5c6b3f24b99ea8149c7 -------------------------------------- - -But there are other ways to refer to commits. You can use any initial -part of the name that is long enough to uniquely identify the commit: - -------------------------------------- -$ git show c82a22c39c # the first few characters of the name are - # usually enough -$ git show HEAD # the tip of the current branch -$ git show experimental # the tip of the "experimental" branch -------------------------------------- - -Every commit usually has one "parent" commit -which points to the previous state of the project: - -------------------------------------- -$ git show HEAD^ # to see the parent of HEAD -$ git show HEAD^^ # to see the grandparent of HEAD -$ git show HEAD~4 # to see the great-great grandparent of HEAD -------------------------------------- - -Note that merge commits may have more than one parent: - -------------------------------------- -$ git show HEAD^1 # show the first parent of HEAD (same as HEAD^) -$ git show HEAD^2 # show the second parent of HEAD -------------------------------------- - -You can also give commits names of your own; after running - -------------------------------------- -$ git tag v2.5 1b2e1d63ff -------------------------------------- - -you can refer to `1b2e1d63ff` by the name `v2.5`. If you intend to -share this name with other people (for example, to identify a release -version), you should create a "tag" object, and perhaps sign it; see -linkgit:git-tag[1] for details. - -Any Git command that needs to know a commit can take any of these -names. For example: - -------------------------------------- -$ git diff v2.5 HEAD # compare the current HEAD to v2.5 -$ git branch stable v2.5 # start a new branch named "stable" based - # at v2.5 -$ git reset --hard HEAD^ # reset your current branch and working - # directory to its state at HEAD^ -------------------------------------- - -Be careful with that last command: in addition to losing any changes -in the working directory, it will also remove all later commits from -this branch. If this branch is the only branch containing those -commits, they will be lost. Also, don't use `git reset` on a -publicly-visible branch that other developers pull from, as it will -force needless merges on other developers to clean up the history. -If you need to undo changes that you have pushed, use `git revert` -instead. - -The `git grep` command can search for strings in any version of your -project, so - -------------------------------------- -$ git grep "hello" v2.5 -------------------------------------- - -searches for all occurrences of "hello" in `v2.5`. - -If you leave out the commit name, `git grep` will search any of the -files it manages in your current directory. So - -------------------------------------- -$ git grep "hello" -------------------------------------- - -is a quick way to search just the files that are tracked by Git. - -Many Git commands also take sets of commits, which can be specified -in a number of ways. Here are some examples with `git log`: - -------------------------------------- -$ git log v2.5..v2.6 # commits between v2.5 and v2.6 -$ git log v2.5.. # commits since v2.5 -$ git log --since="2 weeks ago" # commits from the last 2 weeks -$ git log v2.5.. Makefile # commits since v2.5 which modify - # Makefile -------------------------------------- - -You can also give `git log` a "range" of commits where the first is not -necessarily an ancestor of the second; for example, if the tips of -the branches `stable` and `master` diverged from a common -commit some time ago, then - -------------------------------------- -$ git log stable..master -------------------------------------- - -will list commits made in the `master` branch but not in the -stable branch, while - -------------------------------------- -$ git log master..stable -------------------------------------- - -will show the list of commits made on the stable branch but not -the `master` branch. - -The `git log` command has a weakness: it must present commits in a -list. When the history has lines of development that diverged and -then merged back together, the order in which `git log` presents -those commits is meaningless. - -Most projects with multiple contributors (such as the Linux kernel, -or Git itself) have frequent merges, and `gitk` does a better job of -visualizing their history. For example, - -------------------------------------- -$ gitk --since="2 weeks ago" drivers/ -------------------------------------- - -allows you to browse any commits from the last 2 weeks of commits -that modified files under the `drivers` directory. (Note: you can -adjust gitk's fonts by holding down the control key while pressing -"-" or "+".) - -Finally, most commands that take filenames will optionally allow you -to precede any filename by a commit, to specify a particular version -of the file: - -------------------------------------- -$ git diff v2.5:Makefile HEAD:Makefile.in -------------------------------------- - -You can also use `git show` to see any such file: - -------------------------------------- -$ git show v2.5:Makefile -------------------------------------- - -Next Steps ----------- - -This tutorial should be enough to perform basic distributed revision -control for your projects. However, to fully understand the depth -and power of Git you need to understand two simple ideas on which it -is based: - - * The object database is the rather elegant system used to - store the history of your project--files, directories, and - commits. - - * The index file is a cache of the state of a directory tree, - used to create commits, check out working directories, and - hold the various trees involved in a merge. - -Part two of this tutorial explains the object -database, the index file, and a few other odds and ends that you'll -need to make the most of Git. You can find it at linkgit:gittutorial-2[7]. - -If you don't want to continue with that right away, a few other -digressions that may be interesting at this point are: - - * linkgit:git-format-patch[1], linkgit:git-am[1]: These convert - series of git commits into emailed patches, and vice versa, - useful for projects such as the Linux kernel which rely heavily - on emailed patches. - - * linkgit:git-bisect[1]: When there is a regression in your - project, one way to track down the bug is by searching through - the history to find the exact commit that's to blame. `git bisect` - can help you perform a binary search for that commit. It is - smart enough to perform a close-to-optimal search even in the - case of complex non-linear history with lots of merged branches. - - * linkgit:gitworkflows[7]: Gives an overview of recommended - workflows. - - * linkgit:giteveryday[7]: Everyday Git with 20 Commands Or So. - - * linkgit:gitcvs-migration[7]: Git for CVS users. - -SEE ALSO --------- -linkgit:gittutorial-2[7], -linkgit:gitcvs-migration[7], -linkgit:gitcore-tutorial[7], -linkgit:gitglossary[7], -linkgit:git-help[1], -linkgit:gitworkflows[7], -linkgit:giteveryday[7], -link:user-manual.html[The Git User's Manual] - -GIT ---- -Part of the linkgit:git[1] suite From 6532e60e30864c9bccfe5be0731c6913aa44d188 Mon Sep 17 00:00:00 2001 From: Julia Evans Date: Fri, 25 Sep 2026 11:45:45 -0400 Subject: [PATCH 2/2] doc: add new Git tutorial for beginners Introduce Git in two parts: Steps 1-7: Create an empty repo & make 2 commits (`git init`, `git add`, `git commit`, `git status`, `git diff`) Steps 8-12: Push the repo to a remote host like GitHub or GitLab (`git remote add`, `git push`) Some design choices: - Introduce a much smaller set of commands than the old tutorial, to keep the tutorial quick (doable in an hour). Some users found it to be very fast and some wanted to stop early (after step 7) so this seems to be a good balance. - Have users start with an empty repository instead of an existing project, because many of the testers did not have an existing project to test, or were scared of using an existing project. - Add a troubleshooting section, since in the testing some users got extremely stuck (for 4+ hours) on minor issues like needing to say "yes" when SSHing to a new host. - Don't explain branches, because explaining branches and collaboration is complicated and deserves its own tutorial. Instead just tell users we're not going to explain them in this document. - Tell users to set their default branch to `main`, because many Git hosts use it as their default branch and it really simplifies things. - Keep it as vendor neutral as possible, while acknowledging the reality that Git hosting services like GitHub, GitLab, etc are extremely popular. Do this by creating the repo locally and then optionally pushing it later. - Use SSH for authentication, explaining how to set up SSH in the easiest way possible (with disclaimers to check your security team's policy if applicable since the "easiest way" may not be the best), and giving some instructions for how to translate an HTTPS URL to an SSH URL. At least 20 people have successfully completed it, and feedback was incorporated from problems the testers ran into. Co-authored-by: Marie Claire LeBlanc Flanagan Signed-off-by: Marie Claire LeBlanc Flanagan Signed-off-by: Julia Evans --- Documentation/gittutorial.adoc | 739 +++++++++++++++++++++++++++++++++ 1 file changed, 739 insertions(+) create mode 100644 Documentation/gittutorial.adoc diff --git a/Documentation/gittutorial.adoc b/Documentation/gittutorial.adoc new file mode 100644 index 00000000000000..c8b6f0ebd03304 --- /dev/null +++ b/Documentation/gittutorial.adoc @@ -0,0 +1,739 @@ +gittutorial(7) +============== + +NAME +---- +gittutorial - Introduction to Git for beginners + +DESCRIPTION +----------- + +Git is a program that lets you collaborate with others on code, back up +your code, roll back to an earlier version of your project, track how +your project has changed over time, and much more. + +This tutorial explains how to create a new Git project, make +changes to it, and upload the project to the Internet. It usually takes +less than an hour if you have a little previous experience with Git, and +1-2 hours if not. + +We'll show you how to use the commands `git commit`, `git add`, +`git diff`, `git status`, and `git push`. + +What we'll be doing +------------------- + +Git lets you take snapshots of your code, like a checkpoint in a video +game. These snapshots are called "commits". Which files to save in a +commit is up to you. + +When Git stores a commit, it stores a copy of every file in the commit +in a database in a directory called `.git`. This is called a "Git repository". + +In this tutorial we're going to show you how to: + +1. Create a Git repository in a directory with the command `git init`. + This creates the `.git` directory where Git stores all your commits. +2. Tell Git which files you want to put in a commit +3. Make a commit +4. Change a file and make a new commit with the new version +5. Make experimental changes and throw them away + +We'll also explain how to use Git to put your code on the Internet. + +Command line vs graphical interfaces +------------------------------------ + +Git is a command line program, but there are many graphical interfaces +for Git built by the community. Your text editor might even have a +built-in Git integration. + +In this tutorial, we'll give instructions for using Git from the +command line. We can't give you instructions for how to do it in your +graphical interface because there are so many of them. + +You can always switch back and forth between using the command line and +a graphical interface at any time. + +Step 1: Make sure Git is installed +---------------------------------- + +To do this tutorial, you'll need: + +1. Git to be installed. You might already have it installed, + and if not there are directions at https://git-scm.com/install/ +2. A terminal to use. On Windows, you can use Git Bash which comes + when you install Git. + +You can check if Git is installed by running this in your terminal: + +------------------------------------------------ +$ git --version +------------------------------------------------ + +It should output something like this: + +------------------------------------------------ +git version 2.54.0 +------------------------------------------------ + +The exact version isn't too important: this tutorial is designed to work +with any version of Git after 2.0. + +[[step_2]] +Step 2: Introduce yourself to Git +--------------------------------- + +The first time you use Git on a computer, it's a good idea to tell Git +your name and public email address. If you don't, you'll get a lot of +warnings from Git. To do this, run: + +------------------------------------------------ +$ git config --global user.name "Namey McName" +$ git config --global user.email you@example.com +------------------------------------------------ + +The name and email is so that other people you're collaborating with +can know who made the changes. You can set them to anything you want. + +To check if the name and email have been set, you can run these +commands. They should display your name and email: + +------------------------------------------------ +$ git config user.name +$ git config user.email +------------------------------------------------ + +Next, configure Git to set the default branch name to `main` (instead +of `master`) by running this command. We can't explain what a branch is +yet, but Git is going to +https://sfconservancy.org/news/2020/jun/23/gitbranchname/[make `main` the default soon], +and setting this avoids some extremely annoying problems in Step 14. + +------------------------------------------------ +$ git config --global init.defaultBranch main +------------------------------------------------ + +If there's no output, then it succeeded. + +[NOTE] +It's also possible to set a different email address for every project, +but we're not covering that here. + +Step 3: Create an empty folder and 1 file +------------------------------------------ + +In your terminal, create an empty folder and change directories into it. +Later on you could follow the same steps in this tutorial to take an +existing project and start managing it with Git, but we're going to use +an empty project so that everyone following this tutorial has the exact +same files. + +For example, run these commands to make a folder called `myproject` + +------------------------------------------------ +$ mkdir myproject +$ cd myproject +------------------------------------------------ + +Next, using your text editor, create a file in this directory, so we +have something to work with. + +Make a file called README.md, with these contents: + +------------------------------------------------ +We're doing a Git tutorial! +We need 2 lines in this file so here's a second one +------------------------------------------------ + +Save `README.md` and keep it open in your text editor so you can +easily edit it later. The exact contents aren't too important, but +we'll use those contents in the example output later. + +You can check that the file is in the right place by running `ls`, +like this: + +------------------------------------------------ +$ ls +------------------------------------------------ + +The output should look like this: + +------------------------------------------------ +README.md +------------------------------------------------ + +Step 4: Create a Git repository +------------------------------- + +A Git repository lets you save snapshots of your code. Every time you make a +snapshot, Git stores a copy of the contents of every file in the snapshot. + +This might feel unbelievable, but Git uses compression so you can easily +store tens of thousands of snapshots without using too much disk space. + +You can create a Git repository for any folder in your computer by +running the command `git init`. + +Run `git init` in the folder you just created, like this: + +------------------------------------------------ +$ git init +------------------------------------------------ + +Git will reply: + +------------------------------------------------ +Initialized empty Git repository in .git/ +------------------------------------------------ + +You might notice a new hidden folder was created, named `.git`. +You don't need to use this folder directly in any way, but it's where +your commits will be stored. + +Step 5: Make your first commit +------------------------------ + +Next, we're going to take a snapshot of all the files in the directory +and tell Git to store them. Git calls these snapshots "commits". +Making a commit in Git is a two step process: first you need to run `git +add` and then `git commit`. + +The reason it's a two step process is that sometimes you might not +actually want Git to store a commit with _all_ the files in a folder. +For example, if you're compiling your program to a binary, you might +want Git to put the program's source code in your commit but not +compiled binary. You can also use a `.gitignore` file to help with this. + +For now, we're going to store a commit with every file in your folder, +as well as in every subfolder. + +The first step of making a commit is to tell Git which files you +want to include in the commit using `git add`. To tell Git +"include all files", run this command: + +------------------------------------------------ +$ git add . +------------------------------------------------ + +To check if it succeeded, you can run `git status`. +The output should look like this: + + +------------------------------------------------ +$ git status +On branch main + +No commits yet + +Changes to be committed: + (use "git rm --cached ..." to unstage) + new file: README.md +------------------------------------------------ + +Next you can create the commit using the `git commit` command, like +this: + +------------------------------------------------ +$ git commit -m "Initial commit" +------------------------------------------------ + +The `-m` flag stands for "message", and it lets you set a reminder +for your future self of what you were doing. The message +("Initial commit" in this example) can say anything you want. + +The output should look like this: + +------------------------------------------------ +[main (root-commit) 4a7e367] Initial commit + 1 file changed, 2 insertions(+) + create mode 100644 README.md +------------------------------------------------ + +You've now stored the first version of your project in Git! + +Step 6: Make a change +--------------------- + +Now, let's learn how to make a change to a file and review the change you made. +In this example, we'll update the file `README.md`, but you can edit a +different file. + +First open `README.md` in your favourite text editor, make a tiny or +silly change, and save it. In our example, we'll edit the first line to +add more exclamation marks: + +------------------------------------------------ +We're doing a Git tutorial!!!! +------------------------------------------------ + + +Next, in the terminal, run the command `git status` to get a summary of +what you changed since the last Git commit. + +------------------------------------------------ +$ git status +------------------------------------------------ + +The output will look something like this: + +------------------------------------------------ +On branch main + +Changes not staged for commit: + (use "git add ..." to update what will be committed) + (use "git restore ..." to discard changes in working directory) + modified: README.md +------------------------------------------------ + +This output says that we've changed `README.md` since the last time +we committed. + +Next, if you want to see the details of how you've changed `README.md`, +you can run `git diff`. + +------------------------------------------------ +$ git diff +------------------------------------------------ + +The output will look something like this: + +------------------------------------------------ +diff --git a/README.md b/README.md +index ffa8b85..a49e4b0 100644 +--- a/README.md ++++ b/README.md +@@ -1,2 +1,2 @@ +-We're doing a Git tutorial! ++We're doing a Git tutorial!!!! + We need 2 lines in this file so here's a second one +------------------------------------------------ + +This output says that we deleted one line (`We're doing a Git +tutorial!`) and added one line (`We're doing a Git tutorial!!!!`). By +default Git will show the lines you removed in red, and the lines you +added in green. Removed lines start with a minus `-` and added lines +start with a plus `+`. + +Step 7a: Make a second commit +----------------------------- + +Now that we've changed `README.md`, let's make another commit. +We're going to follow the same steps as before when we made our first +commit. + +First, tell Git that we want to include the new version of `README.md` +in the next commit: + +------------------------------------------------ +$ git add README.md +------------------------------------------------ + +and then run `git commit`, like this: + +------------------------------------------------ +$ git commit -m "Update README" +------------------------------------------------ + +The output should look like this: + +------------------------------------------------ +[main 32e0171] Update README + 1 file changed, 1 insertion(+), 1 deletion(-) +------------------------------------------------ + +This says that the new commit is the same as the previous commit, +except that we changed 1 line of 1 file. + +Step 7b: Make a second commit (the short way) +--------------------------------------------- + +Instead of running the two commands in Step 7a above, you +could also run this command as a shortcut. It will: + +1. Get a list of every file in the most recent commit +2. Commit the current version of all of those files + +------------------------------------------------ +$ git commit -am "Update README" +------------------------------------------------ + +The `-a` stands for "all". + +Understanding `git status` output: "untracked files" +---------------------------------------------------- + +Now let's talk about a term you'll see in the `git status` output: +"untracked files". + +First create a new file called `example.txt`. It can be empty. + +Then run the command `git status`. You should see this output: + +---------- +On branch main + +Untracked files: + (use "git add ..." to include in what will be committed) + example.txt + +nothing added to commit but untracked files present (use "git add" to track) +---------- + +This has a list of "untracked files". An untracked file is a file which +was not part of the latest commit. By default Git will ignore these +files. + +If you want to commit an untracked file, you can add it like this: + +---------- +$ git add example.txt +---------- + +Then you can run `git commit` to commit it. + +Step 8: Make a change and throw it away +--------------------------------------- + +One of the most useful things about Git is that it lets you safely +experiment: you never need to be scared to change your code because you +can always go back to the old version. + +Before starting to experiment, run `git status` to check the current +state of your Git repository: + +------------------------------------------------ +$ git status +On branch main + +nothing to commit, working tree clean +------------------------------------------------ + +This "working tree clean" message means that there haven't been any +changes since your last commit. + +Now make a change to your code, and run `git status` again. Like last +time, you should see a message like this: + +------------------------------------------------ +$ git status +On branch main + +Changes not staged for commit: + (use "git add ..." to update what will be committed) + (use "git restore ..." to discard changes in working directory) + modified: README.md +------------------------------------------------ + +This tells us that `README.md` has been changed since the last commit. +But we don't actually want this change, so let's undo it! We can restore +`README.md` back to how it was at the most recent commit using the `git +restore` command. + +**WARNING**: `git restore` can't be reversed! Any time you run it it's +important to be absolutely sure that you're okay with throwing away your +changes since the last commit. + +------------------------------------------------ +$ git restore README.md +------------------------------------------------ + +Now open `README.md` again. You should see that your changes have been undone. + +You can stop here! +------------------ + +The commands we've learned so far (`git init`, `git add`, `git commit`, +`git diff`, `git status`, and `git restore`) are enough to get a lot out +of Git on their own. + +With these commands, you can keep copies of past versions of your code +on your computer and safely experiment with big changes to your code. + +When using Git this way, all of your code just lives on your computer. +But if you want to put your code on the Internet so that other people +can use it or back it up, then you'll need to learn about one more +command: `git push`. + +The rest of this tutorial is about how to upload your code to a Git +repository on the Internet. The high level process is: + +1. Create an account on the Git host +2. Configure Git so that it can login to the Git host to make changes +3. Run `git push origin main` to upload your code + +Navigating the Git host's UI can be tricky, and it's hard for us to +give you exact directions because the UIs change a lot. +There's a rich tradition of people learning Git from their "Git friend" +who already knows Git, and if you have one of those it might be useful +to ask them if you get stuck. There are many ways to do things in Git, +so they might suggest a slightly different way. +There's also a troubleshooting guide at the end with the most common +issues folks have run into while doing this tutorial. + +Step 9: Create an account on a Git host +--------------------------------------- + +To put your code on the Internet, you need it to be hosted somewhere. +The easiest way to do this is to sign up with a Git host. There's a list +of Git hosts (many of them offer free accounts) at +https://git-scm.com/tools/hosting. GitHub and GitLab are two popular hosts. + +If you're comfortable running a server, there are other ways to host +a Git repository on the internet, like connecting through SSH or open +source Git forge software to your server. + +Step 10: Create an SSH key (if needed) +------------------------------------- + +For Git to upload changes to another Git repository, it needs a way to +login to that repository. One of the most popular ways to do this is +with an SSH key. + +If you don't already have an SSH key, you'll need to create one. On Mac +or Linux, you can check if you already have an SSH key by running: + +------------------------------------------- +$ ls ~/.ssh/*.pub +------------------------------------------- + +If you don't already have an SSH key, run: + +------------------------------------------- +$ ssh-keygen +------------------------------------------- + +`ssh-keygen` will ask you for some details. +The easiest way to do this is to just press Enter at every prompt until +it's done. + +NOTE: All of the advice about how to use SSH in this tutorial is aimed +at getting it to work as quickly as possible. Setting up SSH in a secure +way is very far outside the scope of this tutorial. If you have a +security team in your organization, they might have very different +opinions about the appropriate way to configure authentication with Git. + +Step 11: Tell the Git host your SSH public key +---------------------------------------------- + +First, find your SSH key like this (on Mac or Linux): + +------------------------------------------- +$ ls ~/.ssh/*.pub +------------------------------------------- + +That will output something like + +------------------------------------------- +/home/alice/.ssh/id_ed25519.pub +------------------------------------------- + +Copy the contents of that file to your clipboard. It's important that +the filename ends in `.pub` ("pub" stands for "public"). + +Then login to your account on the Git host you chose and paste the SSH +key into the appropriate place. Depending on the Git host, it's likely +under "SSH keys" in your settings. If it asks you what type of SSH key, +look for something like "Authentication Key". + +Once you've done this, you're done! Git will automatically use your SSH +key to try to connect. + +[[step_12]] +Step 12: Create an empty Git repository on the Git host +------------------------------------------------------- + +Go to the Git host's website and create a new Git repository. If there's +an option to "create a README.md", "add a license", or something +similar, make sure to say no to all of them. + +**WARNING**: If you create a public repository and push your repository +to it, then your name and email address, as well as the contents of +any files you committed and every previous version of those files, will +be on the public internet. Some Git hosts have the option to create +a private repository instead, to keep your information private. + +Step 13: Find the address of the repository +------------------------------------------- + +Now, find the address of the repository on your Git host. It should look +something like this: + +------------------------------------------- +git@git.example.com:username/repo.git +------------------------------------------- + +(where `example.com`, `username` and `repo` will be replaced with the +actual values). + +If you can only find an address starting with `https://`, then +you can often translate it to the SSH format by replacing `https://` +with `git@` and replacing the `/` after the domain name with an `:`. +Here's how: + +------------------------------------------- +https://git.example.com/username/repo +^^^^^^^^ ^ +replace with "git@" replace with ":" +------------------------------------------- + +[[step_14]] +Step 14: push your changes +-------------------------- + +Finally, we're ready to send the information in your local Git repository +to the one on the internet! + +First, tell Git about the other repository by running `git remote add` +in your terminal +(replace `git@example.com:username/repo.git` with the actual address): + +------------------------------------------- +$ git remote add origin git@example.com:username/repo.git +------------------------------------------- + +This tells Git to save the URL `git@example.com:username/repo.git` in +your Git repository's configuration under the name `origin`, so that you +can use it later. If you make a mistake while doing this, you can run +`git remote remove origin` and try again. + +Then tell Git to send the information, with `git push` +(if this doesn't work, read the "Troubleshooting `git push`" section for advice!): + +------------------------------------------- +$ git push --set-upstream origin main +------------------------------------------- + +Let's break down this `git push` command: + +* `origin` refers to the Git repository that we just added with + `git remote add` (`git@example.com:username/repo.git`). + You can use any name (not just `origin`), but using `origin` often + makes things easier because it's the default for `git push` and `git pull`. +* `main` is the name of your current Git branch. + We haven't covered branches yet, but `main` is the default branch name. +* `--set-upstream` tells Git to make this the default for `git push` for + the `main` branch. After you set the upstream, `git status` will + also tell you if you have commits that haven't been pushed. + +The output should look like this: + +------------------------------------------- +Enumerating objects: 7, done. +Counting objects: 100% (7/7), done. +Delta compression using up to 8 threads +Compressing objects: 100% (6/6), done. +Writing objects: 100% (7/7), 662 bytes | 662.00 KiB/s, done. +Total 7 (delta 0), reused 0 (delta 0), pack-reused 0 (from 0) +To example.com:username/repo + * [new branch] main -> main +branch 'main' set up to track 'origin/main'. +------------------------------------------- + +Any time you want to set up a new repository, you can repeat steps +12-14, with one exception: you only need to pass `--set-upstream` the first time +you push. Afterwards you can just run the command: + +------- +$ git push origin main +------- + +Troubleshooting `git push` +-------------------------- + +There are 3 main errors you might run into when running `git push origin main`. +Getting errors when running `git push` is actually a big part of using +Git, so congratulations! If you get to this part of the tutorial, you +get a little bonus experience in debugging. + +Here's a guide to why they're happening and how to fix them. + +**Problem 1: You pushed to `main`, but your branch actually isn't called `main`** + +Here's the error: + +------- +$ git push origin main +error: src refspec main does not match any +------- + +This might happen if you didn't set `init.defaultBranch` to `main` in +<>. + +If you want to check the name of your current branch, you can run `git +status`. For example, in this output, the current branch is "master". + +------------------------------------------- +$ git status +On branch master + +... +------------------------------------------- + +To push your branch, you have a few options: + +* rename your branch to `main`, by running `git branch -m main` + and then run `git push origin main` +* run `git push origin master` + (where `master` is the name of your actual current branch) + +**Problem 2: SSH error** + +Here's the error: + +----- +$ git push origin main +The authenticity of host 'github.com (140.82.116.3)' can't be established. +ED25519 key fingerprint is: SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU +This key is not known by any other names. +Are you sure you want to continue connecting (yes/no/[fingerprint])? +----- + +Git uses SSH to connect during `git push`, and this message happens when +SSH connects to a new site that you haven't connected to before. + +The easiest way to handle this is to type "yes" and press Enter. + +**Problem 3: the repository already has commits in it** + +Here's the error: + +--------------------- +$ git push origin main +! [rejected] main -> main (fetch first) +error: failed to push some refs to 'example.com:username/repo.git' +hint: Updates were rejected because the remote contains work that you do not +hint: have locally. +--------------------- + +If you see an error like this, it means that when you created the +repository on your Git host, it added a commit to try to help you out. +That's the "work that you do not have locally" in the error message. + +You should be able to fix this by redoing <>. +Then <> should work. + +MORE USEFUL GIT COMMANDS +------------------------ + +We're not going to cover collaboration at all in this tutorial, but here are a +few more commands that might be useful when using Git on your own: + +* To download a Git repository to use on your computer you can run + `git clone https://example.com/some/repo` (linkgit:git-clone[1]). +* To tell Git to "un-add" a file that you added by accident, run + `git rm --cached FILENAME` (linkgit:git-rm[1]) +* To get a list of past commits, run `git log` (linkgit:git-log[1]) +* Every commit has an ID that looks something like this: + `497588f53141b531a59ed888c7d2d9b8f8a6742d`. + If you see a commit with `git log` that you want more details about, + you can run `git show COMMIT_ID` to see what changes that made since + the previous commit (linkgit:git-show[1]) + +SEE ALSO +-------- +linkgit:git-help[1], + +GIT +--- +Part of the linkgit:git[1] suite