Merging master into all origin branches using bash

Question

I'm looking for a shell/bash script to do the following Git commands:

• for each branch on remote:
  • merge origin/master

I was able to do it using Python:

tmp_folder = "tmp-clone"
if os.path.exists(tmp_folder):
    shutil.rmtree(tmp_folder)
g = git.Git()
g.execute(["git", "clone", "...", tmp_folder])

g = git.Git("tmp-clone")
branches = g.execute(["git", "branch", "-r"])    
matches = [item for item in re.findall(r"origin/([\w-]+)", branches) if item not in ("HEAD", "master")]

for branch in matches:
    print("merge master -> %s" % branch)
    g.execute(["git", "checkout", branch])
    g.execute(["git", "merge", "master"])
    g.execute(["git", "push"])

But I'm looking to do this without Python. Anyone? My initial guess would be to do something like

for BRANCH in $(git branch -r); (...); done

However, git branch -r outputs

origin/HEAD -> origin/master

origin/master

origin/some_branch_a

origin/some_branch_b

and (in this example) I'm only interested in some_branch_a and some_branch_b (hence the regex in my Python), so I also need some kind of regex in the bash script. However, my bash-scripting skills are quite limited:

for BRANCH in $(git branch -r); 
    if $BRANCH matches "origin/([\w-]+)" ???
        git checkout $BRANCH;
        git merge origin/master;
        git push $BRANCH;
    fi
done

Note: Assume that conflicts can NOT occur.

Answer 1

Your Python code does not do what your text description suggests. The following is based on the code, not the description.

---

Use git for-each-ref , which finds references within some part of the namespace. The namespace here is refs/remotes/origin :

git for-each-ref --format='%(refname:short)' refs/remotes/origin |
while read refname; do
    ...
done

Strip off origin/ :

    name=${refname#origin/}

Check for and discard HEAD and master since you do not want to operate on them:

    case "$name" in
    HEAD|master) continue;;
    esac

(or the same with if if you prefer).

You're now ready to use git checkout $name , git merge master , and git push as before. Note that it's more efficient to do one final git push of every name, but that's a little more complex.

To check whether your script is really ready, before actually doing anything, make it echo the commands it would have done:

git for-each-ref --format='%(refname:short)' refs/remotes/origin |
while read refname; do
    name=${refname#origin/}
    case "$name" in
    HEAD|master) continue;;
    esac
    echo git checkout $name
    echo git merge master
    echo git push $name
done

Note: the above is all untested.