Version control tool Git - introduction, installation, configuration, generating public keys and getting help

What is version control? Generally, as a developer, you must have experienced version iterations. For example, it has been updated and iterated from version 0.01 to 10.3.2, and it has gone through countless versions. If there is no version control tool, then every time a new version is developed, the previous version needs to be backed up. When a problem occurs with the new version, you need to find the old version and replace it with the new version online. Is this operation very troublesome? All version control tools have appeared to help us do these things quickly and conveniently.

Git

As the leader in version control tools, Git has become the version control tool used by most developers. Unlike centralized version control tools, Git is a distributed version control tool, and each client has a complete history record. This has a very big benefit and can prevent single points of failure.

So, does Git have other features?

• Different from other version control systems, Git directly records snapshots instead of differential backups

• Almost all operations are local operations. It can be completed without a network connection, so the speed is very fast.

• The data is very safe and no data will be lost. Because Git will verify every data before saving it.

Workspace, staging area, version library

If you want to learn Git well, you need to understand these three and the connection between the three.

The above picture is a general process of using Git. First, the files in the workspace are temporarily stored in the temporary storage area, and then the contents of the temporary storage area are submitted to the repository. , at this time there is a snapshot of this version in the version library.

Install git

The following describes how to install Git

Installation under windows

To use Git on Windows, you can download the installation program directly from the Git official website and just keep going next. Then right-click on the desktop. If git bash appears, the installation is successful.

Installation under CentOS

yum install git

Git first configuration

Git configuration is divided into three levels: global level, user level, and current warehouse. The configuration at the next level will overwrite the configuration at the previous level. For example, the configuration at the warehouse level will overwrite the user level and global level; the user level configuration will overwrite the global level configuration. Git comes with the git config tool to read and set configuration information. The addresses of these configuration level configuration files are as follows:

• global level, /etc/gitconfig

• user level, ~/.gitconfig

• Warehouse level, .git/config under the current warehouse directory

User information

When we install Git for the first time, all we need to do is set the user name and user email. If these things are not set, it will not be submitted. It is generally recommended to use user-level settings with the option --global. If --global is not used, the warehouse level configuration is set by default.

Next, let’s set the user name and email

$ git config --global user.name "paul"
$ git config --global user.email "paul@163.com"

View the configuration information

After setting it up, let’s To check whether the setting is successful, use git config --list to list all configuration parameters and values.

# git config --list
user.name=paul
user.email=paul@163.com

View single configuration

# git config user.name
paul

Generate public key

Generally, after the first installation, we will also generate a public key. The command to generate the public key is as follows:

ssh-keygen -t rsa -C 'youremail@example.com'

Then press Enter three times. Normally we don't set a password, so we just press Enter. Then, the public key and private key will be generated. You can view the public key content through

cat ~/.ssh/id_rsa.pub

Get help information

There are three equivalent methods to get help information

git help [命令]
git [命令] --help
man git [命令]

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