.bashrc git branch

It is often useful to display your current git branch in your prompt - but not obvious how to do it.

Embedding function calls in the prompt

Example basic prompt:

export PS1="${USER}@${HOST} \w\n"

Example prompt with embedded function call:

export PS1="${USER}@${HOST} \$(date -I) \w\n"

In the example with the embedded call, notice how it is backslash escaped.

Getting the current git branch

git_branch() {
  git status --porcelain -b 2> /dev/null | grep -Po "(?<=^## )[^\.]+" 2>/dev/null
  if [ "$?" -gt 0 ]; then
    echo "--"
  fi
}

git branch() {
  # Save original directory
  local dir="`pwd`"

  # Move upwards through the directory tree until a .git directory is found
  while [ "`pwd`" != "/" ] && ! [ -e ".git" ]; do cd ..; done

  # If it has been found, echo the branch of HEAD, else echo "--"
  if [ -e ".git" ]; then grep -Eo "[^/]+$" .git/HEAD; else echo "--"; fi

  # Restore original directory
  cd "$dir"
}