# 创建一个文件
echo "Hello, world!" > hello.txt
git add .
git commit -m "Initial commit with v1"

# 修改文件内容以创建v2
echo "Hello, Git!" > hello.txt
git add .
git commit -m "Updated to v2"

# 再次修改文件内容以创建v3
echo "Hello, version control!" > hello.txt
git add .
git commit -m "Updated to v3"