README.md

   1 git-cheat-sheet
   2 ===============
   3
   4 How to do stuff with git
   5
   6 Staging a subset of changes in a file
   7 -------------------------------------
   8
   9     git add -p
  10
  11     y - stage this hunk
  12     n - do not stage this hunk
  13     q - quit; do not stage this hunk or any of the remaining ones
  14     a - stage this hunk and all later hunks in the file
  15     d - do not stage this hunk or any of the later hunks in the file
  16     g - select a hunk to go to
  17     / - search for a hunk matching the given regex
  18     j - leave this hunk undecided, see next undecided hunk
  19     J - leave this hunk undecided, see next hunk
  20     k - leave this hunk undecided, see previous undecided hunk
  21     K - leave this hunk undecided, see previous hunk
  22     s - split the current hunk into smaller hunks
  23     e - manually edit the current hunk
  24     ? - print help
  25
  26 https://git-scm.com/docs/git-add#Documentation/git-add.txt-patch
  27
  28
  29 Splitting a repo
  30 ----------------
  31
  32 ##### Remove history of all but select files in cloned repo
  33 ```sh
  34 $ git clone old new
  35 $ cd new
  36 $ git clean -dfx
  37 $ git gc --aggressive --prune=now
  38 $ git remote rm origin
  39 $ git filter-branch \
  40     --prune-empty \
  41     --index-filter '
  42         git ls-tree -r --name-only HEAD \
  43         | grep -v file_i_want_to_keep_1 \
  44         | grep -v file_i_want_to_keep_.. \
  45         | grep -v file_i_want_to_keep_n \
  46         | xargs git rm --cached -r --ignore-unmatch
  47     ' \
  48     HEAD
  49 $ git gc --aggressive --prune=now
  50 ```
  51
  52 ##### Remove history of previously-removed (not in current tree) files
  53 ```sh
  54 $ git log --pretty=format: --name-status \
  55     | awk '$0 != "" {print $2}' \
  56     | sort -u > /tmp/tree.old
  57 $ git ls-tree -r --name-only HEAD > /tmp/tree.new
  58 $ git filter-branch \
  59     --force \
  60     --prune-empty \
  61     --index-filter '
  62         grep -Fvxf /tmp/tree.new /tmp/tree.old \
  63         | xargs git rm --cached -r --ignore-unmatch
  64     ' \
  65     HEAD
  66 ```
  67
  68
  69 Inserting a new root commit
  70 ---------------------------
  71 ```sh
  72 git checkout --orphan $TEMP_BRANCH
  73 git rm -rf *
  74 git commit --allow-empty -m $INIT_COMMIT_MSG
  75 git rebase --onto $TEMP_BRANCH --root $MAIN_BRANCH
  76 git branch -d $TEMP_BRANCH
  77 ```
  78
  79
  80 Deleting all tags, locally and remotely
  81 ---------------------------------------
  82 ```sh
  83 for tag in `git tag`;
  84 do
  85     git tag -d $tag
  86     git push $REMOTE_NAME :refs/tags/$tag
  87 done
  88 ```
  89
  90
  91 Get an older version of a file
  92 ------------------------------
  93
  94 ```sh
  95 git cat-file -p $COMMIT_DIGEST:$FILE_PATH
  96 ```
  97
  98
  99 Splitting a commit
 100 ------------------
 101
 102 From [docs](https://git-scm.com/docs/git-rebase#_splitting_commits):
 103
 104 - Start an interactive rebase with `git rebase -i <commit>^`, where `<commit>`
 105   is the commit you want to split.
 106 - Mark the commit you want to split with the action "edit".
 107 - When it comes to editing that commit, execute `git reset HEAD^`. The effect
 108   is that the HEAD is rewound by one, and the index follows suit. However, the
 109   working tree stays the same.
 110 - Now add the changes to the index that you want to have in the first commit
 111   (`git add`)
 112 - Commit the now-current index with whatever commit message is appropriate now.
 113 - Repeat the last two steps until your working tree is clean.
 114 - Continue the rebase with `git rebase --continue`.
 115
 116
 117 Merge 2 repos
 118 -------------
 119
 120 ```sh
 121 $ ls -1
 122 repo_A
 123 repo_B
 124 $ cd repo_B
 125 $ git remote add repo_A ../repo_A
 126 $ git fetch repo_A --tags
 127 $ git merge --allow-unrelated-histories repo_A/$BRANCH
 128 $ git remote remove repo_A
 129 ```