Git Version Control: Installation, Configuration, Core Commands, Branch & Tag Management, and Code Export

1. Install Git Version Control System

Git's working directory, staging area, and repository meanings

Working directory: the visible folder on your computer.

Staging area: also called stage or index, stored in .git/index .

Repository: the hidden .git folder that holds all history.

Installation and configuration commands:

yum install git -y
git --version
git config --global user.name "chenkang"   # set user name
git config --global user.email "[email protected]"   # set email
git config --global color.ui "true"

Initialize a repository:

git init

Add files and commit:

git add .
git commit -m 'add three file'

Rename a file and commit:

git mv file1 file4
git commit -m 'change file name'

File comparison:

git diff file3               # working tree vs. staging
git diff --cached file3      # staging vs. repository

Reverting changes:

# revert a staged file
git reset HEAD file3
# revert an unstaged file
git checkout -- file3

Branch management:

# create a new branch
git branch dev01
# switch to it
git checkout dev01
# merge master into dev01
git merge master -m 'merge master into dev01'
# switch back to master and merge dev01
git checkout master
git merge dev01 -m 'merge dev01 into master'

Branching principles:

master should be stable and used only for releases.

development occurs on dev (or feature) branches.

individual developers work on personal branches and merge into dev.

use --no-ff for a true merge commit to preserve history.

3. Git Tag Management

Tags give commits a readable alias.

# create a lightweight tag
git tag v1.2
# delete a tag
git tag -d v1.2
# create an annotated tag
git tag -a v1.0 -m 'optimized and bug‑fixed' a119962
# show tag details
git show v1.1

4. Exporting Code with Git Archive

Archive a branch:

git archive --format tar.gz --output "./output.tar.gz" master

Archive a specific commit or directory:

# archive a different branch
git archive --format tar.gz --output "./output.tar.gz" dev01
# archive a specific commit
git archive --format tar.gz --output "./output.tar.gz" 5ca16ac0d603603
# archive selected directories from master
git archive --format tar.gz --output "./output.tar.gz" master

5. Upgrading Git on CentOS

Steps to replace the old Git version (1.8.x) with a newer one (2.23.0):

# install build dependencies
yum install curl-devel expat-devel gettext-devel openssl-devel zlib-devel asciidoc -y
yum install gcc perl-ExtUtils-MakeMaker -y
# remove old Git
yum remove git -y
# download source tarball
wget https://mirrors.edge.kernel.org/pub/software/scm/git/git-2.23.0.tar.xz
# extract and build
tar xf git-2.23.0.tar.xz
cd git-2.23.0
make prefix=/usr/local/git all
make prefix=/usr/local/git install
# add new Git to PATH
echo "export PATH=$PATH:/usr/local/git/bin" >> /etc/profile