git new-feature <branch> [ <remote> ]

gitconfig

[alias]
        # create a new feature branch on the same remote as current branch
        new-feature = "!f() { local feature=$1 remote=$2 base=$3 ; \
                if [[ -z $feature ]] ; then \
                    echo >&2 \"git new-feature <branch> [ <remote> ] \" ; \
                    return 1 ; \
                fi ; \
                if [[ -z $remote ]] ; then \
                    local cur=$( git rev-parse --revs-only --symbolic-full-name HEAD ) ; \
                    cur=${cur#refs/heads/} ; \
                    if [[ -z \"$cur\" || HEAD = $cur ]] ; then \
                        echo >&2 \"current branch unknown\" ; \
                        return 1 ; \
                    fi ; \
                    remote=$( git config branch.$cur.remote ) ; \
                fi ; \
                echo >&2 \"Creating feature branch '$feature' for remote '$remote'\" ; \
                set -x ; \
                git push \"$remote\" \"HEAD:$feature\" ; \
                git checkout -t \"$remote/$feature\" ; \
        } ; f"