Script used to easily create/edit new scripts (Influenced by http://www.commandlinefu.com/commands/view/8050/create-a-new-script-automatically-populating-the-shebang-line-editing-the-script-and-making-it-executable.)

shebang.sh

#!/usr/local/bin/bash4
function stderr {
  echo $@ 1>&2
}

function abspath {
  [[ -d $1 ]] && { cd "$1"; echo "$(pwd -P)"; } || 
    { cd "$(dirname "$1")"; echo "$(pwd -P)/$(basename "$1")"; }
}

# Function to create a new script, make it executable, add the shebang and other 
# docblock comments, then open it in the preferred or specified editor
#
# Examples:
#   # Create a test.sh, add the shebang for bash, open in atom
#       shebang test.sh bash atom
#   # Create a test.sh, add the shebang for bash, open in $EDITOR (or $VISUAL)
#       shebang test.sh bash4 
#
# Todos:
#   1) Should be able to determine the executable by the file extension
#
function shebang {
  declare -A editors

  # The editors should be the full command used to open a file
  #   Replacement Strings:
  #     %script%  - Replaced with scripts absolute path
  #     %wc-l%    - Replaced with the scripts line count
  editors['subl']="/Applications/Sublime\ Text\ 2.app/Contents/SharedSupport/bin/subl --add %script%:%wc-l%"
  editors['atom']="/Applications/Atom.app/Contents/MacOS/Atom --add  %script%:%wc-l%"
  editors['vim']="/usr/bin/vim +%wc-l%  %script%"
  editors['vi']="/usr/bin/vi +%wc-l%  %script%"
  editors['nano']="/usr/bin/nano +%wc-l%  %script%"

  # Make sure a script name is provided
  if [[ -z $1 ]]; then
    stderr "No script name specified"
    return 1
  fi

  declare -A script

  script['arg']="${1}"
  script['abspath']=$(abspath "${script['arg']}")
  script['dirname']=$(dirname "${script['abspath']}")
  script['basename']=$(basename "${script['abspath']}")

  if [[ -a "${script['abspath']}" ]]
  then
    stderr "The script \"${script['abspath']}\" already exists"
    return 1
  fi

  # Create the file
  touch "${script['abspath']}"

  if [[ $? -ne 0 ]]
  then
    stderr "Failed to create a script at ${script['abspath']}"
    return 1
  fi

  # Set the permissions
  chmod +x "${script['abspath']}"

  if [[ $? -ne 0 ]]
  then
    stderr "Failed to add executable permissions to ${script['abspath']}"
    return 1
  fi

  # If an executable was provided (for the shebang line), then verify it exists, and create the shebang
  if [[ -n $2 ]]
  then
    bin=$(which "${2}")

    if [[ $? != 0 ]]
    then
      stderr "Error: Unable to find a \"${2}\" executable in your \$PATH (${PATH})"
      return 1
    else
      # Make the script 
      echo -e "#! ${bin}\n" >> "${script['abspath']}"
    fi
  fi

  docblock_format="# %-10s : %s\n"

  printf "${docblock_format}" "Author" $(whoami) >> "${script['abspath']}"
  printf "${docblock_format}" "Created" $(date +%Y-%m-%d) >> "${script['abspath']}"
  printf "${docblock_format}" "Name" "${script['basename']}" >> "${script['abspath']}"
  printf "${docblock_format}" "Directory" "${script['dirname']}" >> "${script['abspath']}"
  [[ -n $bin ]] && printf "${docblock_format}" "Executable" "${bin}" >> "${script['abspath']}"
  echo -e "\n\n" >> "${script['abspath']}"

  script_wc=$(wc -l "${script['abspath']}" | awk '{print $1}')

  # If a custom editor was specified
  if [[ -n $3 ]]
  then
    # Custom editor specified
    if test "${editors[$3]}"
    then
      #printf "Executing: %s %s\n" "${editors[$3]}" "${script['abspath']}"
      # Specified editor IS in scripts array
      cmd=$(echo "${editors[$3]}" | sed "s|%script%|${script['abspath']}|g")
      cmd=$(echo "${cmd}" | sed "s|%wc-l%|${script_wc}|g")

      #echo "Executing: ${cmd}"
      eval ${cmd}

      if [[ $? -ne 0 ]]; then
        stderr "There was an error while opening ${script['abspath']} using $3"
        return 1
      fi
      
      echo "Successfully opened ${script['abspath']} using $3"
      return 0
    else
      # Specified editor is NOT in scripts array - Check if its an executable
      edit_bin=$(which ${3})

      if [[ $? -ne 0 ]]; then
        stderr "The custom text editor specified \"${3}\" does not exist"
        return 1
      fi

      ${edit_bin} "${script['abspath']}"

      if [[ $? -ne 0 ]]; then
        stderr "There was an error while opening ${script['abspath']} using ${edit_bin}"
        return 1
      fi

      echo "Successfully opened ${script['abspath']} using ${edit_bin}"
      return 0

      fi

  elif [[ -n ${VISUAL} ]] || [[ -n ${FCEDIT} ]] || [[ -n ${EDITOR} ]]
  then
    env_editor=${FCEDIT:-${VISUAL:-${EDITOR:-vi}}}
    ${env_editor} "${script['abspath']}"

    if [[ $? -ne 0 ]]; then
      stderr "There was an error while opening ${script['abspath']} using ${env_editor}"
      return 1
    fi

    echo "Successfully opened ${script['abspath']} using ${env_editor}"
    return 0
  else
    vim "${script['abspath']}"
  fi
}


# /Applications/Sublime\ Text\ 2.app/Contents/SharedSupport/bin/subl --add "${script['abspath']}"