Begin to Learn Git

Commonly-used Git Commands

let current working directory to be called “cwd” for short

Basic

init
add

• add <file>
• add -p <file>: choose which change to commit
  commit: take a snapshot of the added files
  diff
• diff <file>: compare <file> in cwd and file in HEAD
• diff <branch/hash> <file>: compare <file> in cwd and file in <branch/hash>
• diff <branch1/hash1> <branch2/hash2> <file>: compare <file> in <branch1> and <branch2>

Branch & Merge

branch

• branch: look up all the branch infos
• branch <branch>: create a new branch <branch>
checkout
• checkout <branch>
• checkout <file>: copy <file> in HEAD to cwd, one way to throw away changes
• checkout -b <branch>: same as branch <branch>; checkout <branch>
merge
• merge <branch>:
  • if HEAD is the ancestor of <branch>, then promote the HEAD->branch and merge with <branch>
  • else, a merge conflict occurs, and remains to by solved by the user
• merge --continue: tell git the merge has finished]
• merge --abort: come back to the state before you call merge

Remote

remote

• remote add <remote> <URL>
push
• push <remote> <local branch>:<remote branch>
• branch --set-upstream-to=<remote branch>
• branch -vv
• push
clone
• clone <URL>
• clone --shalow: only clone the latest snapshot
  fetch
• fetch <remote>
pull
• = fetch + merge
• you can take it as updating the pointers in addition to the snapshots

Other

one of the key algorithm behind git is the Delta Compression Algorithm

• blame
• stash
  • stash pop
• bisect: for debug
• the .gitignore file: filenames and patterns that you want git to ignore