Git pull origin/master branch to local/master, when in local/develop

If you want to update your local master without checkout, you can do :

git pull origin master:master

That will update your local master with the origin/master

Or, as I assume that you want to ultimately rebase your develop branch with the changes occured in origin/master, you can do a simple git fetch, that will not touch your local branches :

git fetch

Now your origin/masteris up to date, so you can rebase or merge your local branch with these changes. For example, when you are in your develop branch :

git rebase origin/master

And your develop branch will be up to date with the changes.