Experiences of Using Commonly Used Git Commands in Linux

Git is a distributed version control software, originally created by Linus Torvalds and released in 2005 under the GPL license agreement. The original purpose was to better manage Linux kernel development. Git is a version control tool used for Linux kernel development. Unlike centralized version control tools such as CVS and Subversion, it uses a distributed version library approach and can operate version control without server-side software, making the release and communication of source code extremely convenient. Git is very fast, which is naturally important for large projects such as the Linux kernel. The most outstanding feature of git is its merge tracing capability. This article briefly introduces the commonly used commands in the use of git

1. First set your username and email

git config --global user.name "nmy" 

git config --global user.email "nmy@weathink.com" 

git config --global --list 

user.name=ken 

user.email=ken@gmail.com 

Among them, --global indicates that user.name and user.email are global variables. The so-called global variables are valid in any version library on your PC. user.name and user.email represent user name and email address respectively. We can use --list to list the contents we have set. It should be noted that user.name and user.email must be set so that we can know who has modified the project in the future. In fact, there are more than 130 options that can be set in git, but most of them are not commonly used.

2. Git output color settings   

git config --global color.ui "always" 

git config --global --list 

user.name=ken 

user.email=ken@gmail.com 

color.ui=always 

If you find that all the colors displayed when using git branch are black and white, it means that the colors are not configured correctly. Please use the git config --global color.ui "always" command.

3. Create a repository

mkdir project

cd project/ 

git init 

Initialized empty Git repository in /home/ken/project/.git/ 

In the above operation, we first created the project directory, and your project files are stored in this directory. Then execute: git init in the directory. OK. It's very simple. At this time, a .git directory will be generated in the /project/ directory, which can be seen by ls -a. Switch to this directory and you will see some files and directories, which are mainly used to store the metadata of the version library.

4、git add 和 git commit

For kernel sources, since .config is not included in git, you need to

git add .config

Then modify .config and make through make menuconfig, and then use the git status command to view the file modifications in the git directory. At this time, you can see that many intermediate .o files have been modified, and many .o files will be listed, such as

# modified:   .config

# .config.old

# drivers/usb/core/.config.o.cmd

# drivers/usb/core/config.o

# include/config/

# kernel/.config_data.gz.cmd

# kernel/.config_data.h.cmd

# kernel/.configs.o.cmd

# kernel/configs.o

But these intermediate files are not what we need. If we are sure to modify .config, we need to submit .config at this time. Use git commit -a -m "modif config", which will submit all the files added in git. If there are other file modifications at this time, they will also be submitted.

At this time, enter the command

git log

It will display all the information submitted before

git log -1

It will display the information of the most recent submission

5、git branch

View all branches

As shown below

root@desktop:~/pru-eight-suart-smard-card-20110912/pru-linux-drivers# git branch

* DIR

master

The asterisk indicates the current branch

If you need to delete a branch, enter the command

git branch -D rrrr

Add branch command

git branch sub_1 master

The third parameter is the new branch, and the fourth parameter indicates the parent branch. Here our parent branch is the main branch master. So this command is to create a new branch sub_1 on the main branch master.

Switch branches, such as

git checkout sub_1

6、git help

Enter the help command

7. Release version

git tag 1.0 sub_1

git tag

1.0

In the first instruction above, the third parameter is the tag, and the last one is the dot indicating the tag; next, the last thing we need to do is to package the released version into a tar or zip package. The command git archive can achieve this function:

git archive --format=tar --prefix=helloworld-1.0/ 1.0 | gzip > helloworld-1.0.tar.gz 

8. git checkout to remote branch

git branch -r

origin/DIR

  origin/HEAD -> origin/master

  origin/master

  origin/pru-migration

  origin/pru1-migration

  origin/sc-driver-dev

  origin/sc-driver-dev-pru1

  origin/sc-test

  origin/suart-driver-dev

Then git checkout origin/DIR

9. git status -u normal prohibits outputting files that have not been added

10. Install gitk graphical interface, which can easily manage and view git branches and commits

apt-get install gitk

Start the graphical git interface

Figure 1, gitk effect diagram

11. qgit graphical interface, qgit is developed using git, and the effect is better

apt-get install qgit

When using qgit, you can check the display All Branches when starting, and then you can display the switching between all branches. This function is very good, equivalent to a tree diagram

git ls-files displays all files in the warehouse.

git ls-files -m displays modified files.

git reset SHA1 returns to the commit status corresponding to SHA1.

Figure 2. qgit effect diagram

10. Delete files in git add

If you have previously operated git add 123

git rm -f 123 to delete 123 in the git repository, and delete the file 123

Or git rm --cached 123 to delete 123 in the git repository, do not delete the file directly

If you want to delete all types of files, you can

git rm --cached -r *.txt

The Linux SOM launched by Weathink all use git to manage code and project branches, such as:

Renesas G2L SOM : https://www.weathink.com/products/hexinban/4.html

TI AM62x SOM: https://www.weathink.com/products/hexinban/11.html