Using Git

Clone one branch or tag, w/o history, with submodules w/o their history (shallow)

  git clone -b v1.2.3 --recurse-submodules --shallow-submodules --depth 1 [repo] 

Update a tag / release

Use variables to point to the GitHub tag you want to update, the temp branch and the tag ref For example 5.12 or v5.12:

tag=v1.2.3
btag="b$tag"
ttag="refs/tags/$tag"

Create and switch to a temporary branch (b) from the current tag (t)
```
  git fetch origin --tags
  git switch -c "$btag" "$tag"
```

Make changes, commit and push

  git commit -am "Fixes for $tag"
  git push -u origin "$btag"

Delete old local tag, recreate tag at HEAD

  git switch "$btag"
  git tag -d "$tag"        
  git tag "$tag"            

Delete old remote tag, push the new tag

  git push origin :"$ttag"
  push origin tag "$tag"

Update the GitHub release: delete and create new one using new tag

Cleanup: delete remote temp branch, local temp branch

  git push origin --delete "$btag"
  branch -D "$btag"

Branches

Create new branch and switch to it:

git checkout -b branchname

Switch to an existing branch:

git checkout branchname

Merge changes from branch1 into branch2 (one of them can be main). Use rebase for a clean history. Alternatively, you can use merge to keep the history of both branches.

git checkout branch2
git merge/rebase branch1 

If conflicts arises:

Open each conflicted file (<<<<<<<, =======, >>>>>>> markers).
Manually resolve the conflicts by editing the file.
After resolving conflicts, mark the files as resolved:
```
git add conflicted_file
```

If necessary, keep one version of the other of one file:

git checkout --ours conflicted_file  # Keep our version (the rebase source)
git checkout --theirs conflicted_file  # Keep their version (the rebase target)

After choosing one version, you still need to git add the file to mark it as resolved.

git add conflicted_file

Finalizing rebase (notice commit w/o message):

git rebase --continue
git push origin branch2

The status can be:

DD unmerged, both deleted
AU unmerged, added by us
UD unmerged, deleted by them
UA unmerged, added by them
DU unmerged, deleted by us
AA unmerged, both added
UU unmerged, both modified

Push a branch to remote:

git push -u origin branchname

Delete a remote branch:

git push origin --delete branchname

List all remote branches:

git branch -r: lists all remote branches
git branch -a: lists all branches (local and remote)
git branch -vv: lists all branches with their last commit
git branch --merged: lists branches that have been merged into the current branch
git branch --no-merged: lists branches that have not been merged into the current branch