Add merging 2 repos

[git-cheat-sheet.git] / README.md

diff --git a/README.md b/README.md
index bca3d59..7b84aca 100644 (file)
--- a/README.md
+++ b/README.md
@@ -7,9 +7,9 @@ How to do stuff with git
 Splitting a repo
 ----------------
 
-### Remove history of all but select files in cloned repo
+##### Remove history of all but select files in cloned repo
 ```sh
-$ cp -Rp old new
+$ git clone old new
 $ cd new
 $ git clean -dfx
 $ git gc --aggressive --prune=now
@@ -27,9 +27,80 @@ $ git filter-branch \
 $ git gc --aggressive --prune=now
 ```
 
-### Remove history of previously-removed (not in current tree) files
+##### Remove history of previously-removed (not in current tree) files
 ```sh
-$ git log --pretty=format: --name-status | awk '$0 != "" {print $2}' | sort -u > /tmp/tree.old
+$ git log --pretty=format: --name-status \
+    | awk '$0 != "" {print $2}' \
+    | sort -u > /tmp/tree.old
 $ git ls-tree -r --name-only HEAD > /tmp/tree.new
-$ git filter-branch --prune-empty --index-filter 'grep -Fvxf /tmp/tree.new /tmp/tree.old | xargs git rm --cached -r --ignore-unmatch' HEAD
+$ git filter-branch \
+    --prune-empty \
+    --index-filter '
+        grep -Fvxf /tmp/tree.new /tmp/tree.old \
+        | xargs git rm --cached -r --ignore-unmatch
+    ' \
+    HEAD
+```
+
+
+Inserting a new root commit
+---------------------------
+```sh
+git checkout --orphan $TEMP_BRANCH
+git rm -rf .
+git commit --allow-empty -m $INIT_COMMIT_MSG
+git rebase --onto $TEMP_BRANCH --root $MAIN_BRANCH
+git branch -d $TEMP_BRANCH
+```
+
+
+Deleting all tags, locally and remotely
+---------------------------------------
+```sh
+for tag in `git tag`;
+do
+    git tag -d $tag
+    git push $REMOTE_NAME :refs/tags/$tag
+done
+```
+
+
+Get an older version of a file
+------------------------------
+
+```sh
+git cat-file -p $COMMIT_DIGEST:$FILE_PATH
+```
+
+
+Splitting a commit
+------------------
+
+From [docs](https://git-scm.com/docs/git-rebase#_splitting_commits):
+
+- Start an interactive rebase with `git rebase -i <commit>^`, where `<commit>`
+  is the commit you want to split.
+- Mark the commit you want to split with the action "edit".
+- When it comes to editing that commit, execute `git reset HEAD^`. The effect
+  is that the HEAD is rewound by one, and the index follows suit. However, the
+  working tree stays the same.
+- Now add the changes to the index that you want to have in the first commit
+  (`git add`)
+- Commit the now-current index with whatever commit message is appropriate now.
+- Repeat the last two steps until your working tree is clean.
+- Continue the rebase with `git rebase --continue`.
+
+
+Merge 2 repos
+-------------
+
+```sh
+$ ls -1
+repo_A
+repo_B
+$ cd repo_B
+$ git remote add repo_A ../repo_A
+$ git fetch repo_A --tags
+$ git merge --allow-unrelated-histories repo_A/$BRANCH
+$ git remote remove repo_A
 ```