git-usage

Some notes on Git

Difference between ^ and ~

commit^n choose the nth parent of the commit

HEAD^ = HEAD^1 = HEAD~ = HEAD~1

G   H   I   J
 \ /     \ /
  D   E   F
   \  |  / \
    \ | /   |
     \|/    |
      B     C
       \   /
        \ /
         A

A =      = A^0
B = A^   = A^1     = A~1
C = A^2
D = A^^  = A^1^1   = A~2
E = B^2  = A^^2
F = B^3  = A^^3
G = A^^^ = A^1^1^1 = A~3
H = D^2  = B^^2    = A^^^2  = A~2^2
I = F^   = B^3^    = A^^3^
J = F^2  = B^3^2   = A^^3^2

See What’s the difference between HEAD^ and HEAD~ in Git?

Clone

Clone a repository with its submodules (--recurse-submodules)

git clone --recurse-submodules git@domain.tld:repo.git`

Add & Move & Remove

Add file in a interactive patch way (-p/--patch)

git add -p <file>

Move (Rename) file and then stage: git mv <filename1> <filename2>
Remove file: git rm <file>
Remove file in index only: git rm --cached <file>

Commit

• Automatically stage changes, add signoff, GPG-sign the commit: git commit -asS
• Fast modify last commit: git commit --amend

Log

• Show log in a friendly format: git -P log --pretty='format:%C(auto)%G?%d %h %an %ar %s' --graph --all
• Show commits with diff patch (-p/-u/--patch/--cc (dense)): git log -cc, git log --cc -1 (For HEAD only)
• Show commits for a user (--author=/--committer=): git log --author=<pattern>
• Grep in commit logs: git log --grep=<pattern>

Diff

• Show a summary: git -P diff --stat
• Show diff of the last commit: git -P diff HEAD HEAD~1 or git -P diff HEAD^!

Blame

Show each line of a file with last commit hash and author: git blame <file>

Stash

git stash
git stash pop

Branch & Remove

Create a branch and set its upstream (-t/--track): git branch <new-branch> <remote-branch>
Delete a branch (-d/--delete): git branch -d <branch>
Delete a remote branch (-d/--delete): git push <remote> -d <branch> / git push <remote> :<branch>
Rename a branch (-m/--move): git branch -m <old-branch> <new-branch>
To rename a remtoe branch, first delete the remote branch, then push a branch with new name: git push <remote> :<old-branch>; git push <remote> <new-branch>

Add remote and choose a branch to track: (-t/--track): git remote add -t <remote-branch> <remote-name> <url>

Tag

tag current HEAD: git tag <tag-name>
push tags (under refs/tags): git push --tags

Rebase

Modify last 10 commits: git rebase -i HEAD~10

• pick doesn’t change this commit
• drop drop this commit
• edit edit this commit
• squash merge this commit with one commit above

Reset & Clean

Reset work tree and delete untracked files: git reset --hard HEAD; git clean -fdx

Reset:

• --soft only change HEAD to <commit>
• --mixed reset index only.
• --hard reset both index and working tree
• --keep reset working tree only (If a file differ between <commit> and HEAD, and also has modified copy in index, this reset will be abort)

Clean:

• -f --force allow git clean to delete files or directories while clean.requireForce is not set to false.
• -d Normally, when no is set, git clean will not recurse into untracked directories to removing too much. Specify -d to have it recurse into such directories as well.
• -x Remove ignored files and directories mentioned in .gitignore

Restore

Restore a file from specify commit: git restore -s <commit> <file>

Rvert

Create a revert commit (Useful when in a team): git revert <commit>
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Submodule

Show submodule status: git submodule status
Add a submodule: git submodule add -b <remote-branch> [--name <name>] <url>
Initialize and update submodule to superproject’s recorded commit SHA-1: git submodule update --init or git submodule init; git submodule update
Update submodule to its remote-tracking branch: git submodule update --remote <submodule-name>

Specify how differences in submodule are shown when using git diff: git diff --submodule=[diff|log|short]

Push only when submodule commits are available on remote-tracking branch: git push --recurse-submodules=check
Push also submodule commits: git push --recurse-submodules=on-demand

Run command in each submodules: git submodule foreach <command>

More Greater Submodule for Git

使用git-subrepo

然后使用git subrepo为开头

还可将子目录变为子仓库:

$ git subrepo init <subdir> [-r <remote>] [-b <branch>] [--method <merge|rebase>]

Git Cherry-pick

git cherry-pick用于把另一个本地分支的commit修改应用到当前分支

假设dev分支有一个hash为38361a68的commit

$ git checkout master
$ git cherry-pick 38361a68

Git Format-patch

1. Create patch files between two commit

   $ git format-patch <r1>..<r2>

2. Single commit patch

   $ git format-patch -1 <r1>

3. Create patch file since commit r1 (But doesn’t include this commit)

   $ git format-patch <r1>

4. Apply series of patches

   $ git am *.patch

Limit memory usage of git-gc

$ git config --global pack.windowMemory "100m"
$ git config --global pack.packSizeLimit "100m"
$ git config --global pack.threads "1"