Untitled

#!/bin/bash
function echo_and_run() {
  echo -ne "\033[1;32m"
  echo -n  "$@"
  echo -e  "\033[0m"
  "$@"
}

BRANCH=$(git symbolic-ref HEAD)
RESULT=$?
if [[ "$RESULT" -ne 0 ]]; then
  exit $RESULT
fi
if [[ "$BRANCH" =~ ([^/]+$) ]]; then
  BRANCH=${BASH_REMATCH[1]}
else
  echo Cannot find the current branch.
  exit 128
fi

# Pull from origin
if git branch -r | grep -qE "^\\s*origin/$BRANCH($|\s)"; then
  echo_and_run git pull --ff-only origin "$BRANCH"
  RESULT=$?
  if [[ $RESULT -ne 0 ]]; then
    exit $RESULT
  fi
else
  echo "Remote branch 'origin/$BRANCH' does not exist."
  echo "Run 'git push origin "$BRANCH"' to push to the origin."
  exit 128
fi

# Check if the current workdir is clean with no additional commit
STATUS=$(git status)
PUSH_TO_ORIGIN=false
if [[ "$STATUS" =~ (working directory clean) &&
      ! "$STATUS" =~ (# Your branch is ([a-z]*) of [^ ]+ by ([0-9]*) commit) ]]; then
  PUSH_TO_ORIGIN=true
fi

# Pull from upstream (if available)
if git remote | grep -qE '^upstream$'; then
  echo_and_run git pull --ff-only upstream "$BRANCH"
  RESULT=$?
  if [[ $RESULT -ne 0 ]]; then
    exit $RESULT
  fi

  # Push the commits from upstream if necessary
  if $PUSH_TO_ORIGIN; then
    STATUS=$(git status)
    if [[ "$STATUS" =~ (working directory clean) &&
          "$STATUS" =~ (# Your branch is ahead of [^ ]+ by ([0-9]*) commit) ]]; then
      echo_and_run git push origin "$BRANCH"
    fi
  fi
fi