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     --prune-empty \
  60     --index-filter '
  61         grep -Fvxf /tmp/tree.new /tmp/tree.old \
  62         | xargs git rm --cached -r --ignore-unmatch
  63     ' \
  64     HEAD
  65 ```
  66
  67
  68 Inserting a new root commit
  69 ---------------------------
  70 ```sh
  71 git checkout --orphan $TEMP_BRANCH
  72 git rm -rf *
  73 git commit --allow-empty -m $INIT_COMMIT_MSG
  74 git rebase --onto $TEMP_BRANCH --root $MAIN_BRANCH
  75 git branch -d $TEMP_BRANCH
  76 ```
  77
  78
  79 Deleting all tags, locally and remotely
  80 ---------------------------------------
  81 ```sh
  82 for tag in `git tag`;
  83 do
  84     git tag -d $tag
  85     git push $REMOTE_NAME :refs/tags/$tag
  86 done
  87 ```
  88
  89
  90 Get an older version of a file
  91 ------------------------------
  92
  93 ```sh
  94 git cat-file -p $COMMIT_DIGEST:$FILE_PATH
  95 ```
  96
  97
  98 Splitting a commit
  99 ------------------
 100
 101 From [docs](https://git-scm.com/docs/git-rebase#_splitting_commits):
 102
 103 - Start an interactive rebase with `git rebase -i <commit>^`, where `<commit>`
 104   is the commit you want to split.
 105 - Mark the commit you want to split with the action "edit".
 106 - When it comes to editing that commit, execute `git reset HEAD^`. The effect
 107   is that the HEAD is rewound by one, and the index follows suit. However, the
 108   working tree stays the same.
 109 - Now add the changes to the index that you want to have in the first commit
 110   (`git add`)
 111 - Commit the now-current index with whatever commit message is appropriate now.
 112 - Repeat the last two steps until your working tree is clean.
 113 - Continue the rebase with `git rebase --continue`.
 114
 115
 116 Merge 2 repos
 117 -------------
 118
 119 ```sh
 120 $ ls -1
 121 repo_A
 122 repo_B
 123 $ cd repo_B
 124 $ git remote add repo_A ../repo_A
 125 $ git fetch repo_A --tags
 126 $ git merge --allow-unrelated-histories repo_A/$BRANCH
 127 $ git remote remove repo_A
 128 ```