Git from entry to earth

Introduction to Git

Git is a distributed version control software that must be used in development. This is its official website Git .

We can find its documentation on the official website, which is very detailed and easy to use.

Download and install

The official website documentation is very detailed, which contains the installation steps of weindows, Linux, and mac. Here is an example of Windows:

After the download is complete, just click the next step. After the installation is complete, right-click the mouse on the desktop. If the following two selection instructions appear, the installation is complete

Local warehouse

Since Git is a distributed version control software, the first thing we have to learn is how to submit the code locally and then to the remote code base.

Version submission

In Git, the first thing we need to do is to manage a project.

Enter the project folder and execute the initialization command to allow Git to take over the version control of the current project. As follows

Then right click, select Git Bash Here and enter the terminal, let Git take over the MyProject folder.

Then enter git init (turn this directory into a warehouse that can be managed by Git). When the command takes effect, a hidden folder of .git will be generated, as shown below

Then we can use git status to check the status of the files being managed in the current folder.

At this time, the newly added files and the modified files are all unmanaged files and are shown in red, as shown above.

At this time, we need to manage the file, use the add command to tell git to add the file to the warehouse.

git add folder name# manage only one file
git add. # Represents all files in the current directory

When we manage and then use git status to check the status, it turns green, and then use git commot to tell Git to submit the file to the warehouse, as shown below:

Here Git tells you that it is abnormal again, let you configure user information, enter account password and other information. We only need to configure the personal information according to the prompts. After configuration, submit it again as shown below:

At this point, we have completely submitted our files to the remote warehouse. You can use git log to check the generated version.

Let's summarize the commands we just used:

command	description
git init	Initialize git, let Git take over the current folder
git status	View the current file status, newly added or modified files are all red, and green after the add command is executed
git add [./filename]	Submit the file
git commit -m "Describe the message"	Generate a version
git log	View version information.

Version rollback

Roll back from high version to low version
- First use git log to view the commit log
- Then use git reset --hard version number to roll back

The same can also be rolled back from a low version to a high version
- First of all, you can't use git log but use git reflog to view the log
- Then use git reset --hard version number to roll back

As usual, let’s summarize

command	description
git log	View version submission information, used for high version rollback low version
go reflog	View version submission information, used for lower version to roll back higher version
git reset --hard version number	Perform version rollback

Partition concept

In the above operation, we can find that a file has multiple states:

In control state: refers to the state in which the file can be managed by git. At present, all files located in the git init folder are in control state
Change status: when there is a new file, or the original file is modified, use git status to show the file in red
Temporary area status: refers to the file whose red status changes to green status after the git add command is executed
Repository status: refers to the version submitted to the version after executing the git commit command

These different states correspond to different partitions. Since what we are doing is local version control at this time, the version library here is the local version library.

Use branch

Branching is a very important concept in Git. It allows you to deal with more emergencies and allows you to better develop collaborative operations. Let you in development, multiple branches do not affect each other, there are official versions, and development versions, etc., as shown below

In this way, the committed versions we see in different branches are not the same. When a new branch is created in a branch, the sub-branch will inherit all the files in the current branch node, and there is a master branch by default.

Common commands are as follows

command	description
git branch	View all branches of the current project (* before the branch indicates the current branch)
git branch branch name	Create a new branch
git checkout branch name	Switch branch
git merge the branch to be merged	Merge branches (switch branches first)
git branch -d branch name	Delete branch

Merge conflict

Due to branch conflicts, multiple branches may modify the same code. At this time, there is a merge conflict problem. Since Git does not know who is listening, you will keep them all and you can modify them manually.

Remote push

The above is very lively, but they are all based on local warehouses. When they are actually used, they have to cooperate with other people. This is also a big advantage of Git.

Git is a distributed version control software. There are many remote version libraries to choose from. Here is our most commonly used GItHub.

The first is to register a user, so I won’t demonstrate it here.

Create warehouse

When we log in to GitHub, the first thing we need to do is to find a remote repository. First open the warehouse page now,

Then click NEW to create a new warehouse, as shown below

After the creation is complete, you will see the following page

So far our warehouse is created, and it can be used later

Push code

Follow the above prompts to start pushing the code to GitHub

git remote add origin https://https://github.com/iszhonghu/Test.git
git push -u origin master

Then you can see that our file was successfully uploaded

This is just the master branch uploaded. If you want to upload the dev branch, you still need to enter the push command

git push -u origin dev

to sum up:

command	description
git remote add alias warehouse address	Give the warehouse an alias
git push -u origin branch name	Push branch to remote warehouse

have to be aware of is:

When pushing code, you need to push one by one branch

Pull code

Now that you can push the code, you can also pull the code to facilitate the realization of collaborative office.

First, create a folder to save the code, and then just pull it directly,

command	description
git clone remote warehouse address	Clone all the codes of the remote warehouse (only for the first time)
git pull origin branch name	Incrementally update the code in a branch

Partition concept

Because it involves a remote warehouse, there is one more partition, as shown below

The pull using incremental update can actually be split into two commands

The git fetch origin branch pulls the branch code in the remote repository to the local repository
git marge origin branch merges the code in the local repository into the local branch

Other operations

Configuration file

The Git configuration file has three parts:

Warehouse-level configuration file: In the warehouse's .git/.gitconfig, the configuration file is only valid for the warehouse where it is located.
- local
Global configuration file: Mac system is in ~/.gitconfig, Windows system is in C:\Users<user name>.gitconfig.
- global
System-level configuration file: gitconfig in the etc folder of the Git installation directory (the installation directory under Mac system is /usr/local/git).
- system

SSH

Use SSH to push and pull code

Generate public key and secret key
- ssh-keygen
- - The default is placed in the /.ssh directory, where id_rsa.pub is the public key and id_rsa is the private key

to sum up

Here are some commands in this article:

command	description
git init	initialization
git status	Check status
git add	Manage specified files
git commit -m "description"	Build version
git log	View version history (previously)
go reflog	View version history (after)
git reset --hard version number	Version rollback
git branch	View all branches
git branch branch name	Create new branch
git checkout branch name	Switch branch
go merge	Branch merge
git branch -d branch name	Delete branch
git remote add alias address	Alias for remote warehouses
git push -u alias branch	Push a branch to a remote warehouse
git clone address	Clone remote warehouse code
git pull alias branch	Pull the code of a branch in the remote warehouse and update incrementally
git rebase -i HEAD~number of entries	Version merge

At last

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