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about reademe
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1. new git dir: learngit;
2. cd learngit;
3. git init;
4. touch readme.txt;
5. vi readme.txt;
6. so,we are here;



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about git
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1. git is a distributed version control system;
2. git is a free software;
3. git is developed by linus;
4. git has a matable index called stage;

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how git works
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1. git tracks changes;