bash script that resets and force pushes

reset_push

#!/bin/bash
# resets HEAD back one commit, recommits with provided message and force pushes to origin

commitmsg=$1

# stole function from: .oh-my-zsh/lib/git.zsh
function current_git_branch() {
  local ref
  ref=$(command git symbolic-ref --quiet HEAD 2> /dev/null)
  local ret=$?
  if [[ $ret != 0 ]]; then
    [[ $ret == 128 ]] && return  # no repo
    ref=$(command git rev-parse --short HEAD 2> /dev/null) || return
  fi
  echo ${ref#refs/heads/}
}

# exit if no commitmsg
if [ -z "$commitmsg" ]
then
    echo "\$commitmsg is empty"
else
    echo "\$commitmsg is NOT empty"
    # output cmds as they run
    set -x

    git reset HEAD~1
    git add .
    git commit -m "$commitmsg"
    git push origin $(current_git_branch) -f
fi