template_script.sh

#!/usr/bin/env bash
set -o errexit -o errtrace -o nounset -o pipefail # Robust scripting.

# Find real script name and location...
cd .;origDir="$PWD";origScript="${BASH_SOURCE[0]}";[[ $origScript != */* ]]&&origScript="./$origScript"
realScript="$origScript";scriptName="${origScript##*/}";scriptDir="${origScript%/*}"
while [[ -L $realScript ]];do cd "${realScript%/*}";realScript="$(readlink "${realScript##*/}")";[[ $realScript != */* ]]&&realScript="./$realScript";done
cd -P "${realScript%/*}";realScript="$PWD/${realScript##*/}";realDir="$PWD";realName="${realScript##*/}";cd "$origDir"

#
# Expanding help...
#
display_help() {
  cat << :END
TODO: Rename this template script.
Usage: $scriptName [options] ...
:END

  if [[ ${1:-} = "--help" ]]; then
    cat << :END
TODO: Replace this text with a short description of the scripts purpose.
This $scriptName script can be used as a basis for command-line scripts.

Options:
  --todo    Add options with parameter description here.

  -h        Display usage.
  --help    Display this help.
  --verbose Display verbose messages.
  --debug   Display debug (very verbose) messages.
  --trace   Display execution trace.
:END
  else
    echo "Try --help for more."
  fi
}

#
# Verbose Echo...
#
exec 3>/dev/null

v_echo() {
  local rc=$?
  if [ $rc -gt 0 ]; then
    echo "$* (RC $rc)" >&3
  else
    echo "$*" >&3
  fi
}

v_var() {
  echo "$1=\"${!1}\"" >&3
}

#
# Exit script due to error...
#
die() {
  local rc=$?
  if [ $rc -gt 0 ]; then
    echo "$scriptName: ${*:-Died} (RC $rc)" >&2
  else
    echo "$scriptName: ${*:-Died}" >&2
  fi
  exit 1
}

#
# Parse arguments...
#
if [[ $# -eq 0 || $1 = "-h" || $1 = "--help" ]]; then
  # Check for help option...
  display_help "$@"
  exit 0
fi

args=( "$@" )
for (( arg=0; arg < ${#args[@]}; arg++ )); do
  opt="${args[arg]:-}"
  param="${args[arg + 1]:-}"

  case "$opt" in
    # TODO: Add script-specific options here...
    --todo)     todo="$param"         # Set the TODO option.
                arg=$(( $arg + 1 ));; # Skip the parameter for the next arg.

    -v|--verbose) exec 3>&2;;         # Redirect verbose output to stderr.
    -x|--debug)   set -o verbose;;    # Display each line of script.
    -xx|--trace)  set -o verbose      # and...
                  set -o xtrace;;     # Trace evaluated statements.

    --) arg=$(( $arg + 1 ))           # No more options (point at next argument).
        break;;

    -*) die "Invalid option $opt specified. Try --help.";;

    *)  break;;                   # No more options.
  esac
done
shift $arg
unset args arg opt param

#
# Initialise variable defaults and display variables...
#
v_echo "Orig Script: $origScript"
v_echo "Script Name: $scriptName"
v_echo "Script Dir:  $scriptDir"
v_echo "---"
v_echo "Real Script: $realScript"
v_echo "Real Name:   $realName"
v_echo "Real Dir:    $realDir"
v_echo "---"
v_echo "Orig Dir:    $origDir"
v_echo "Curr Dir:    $(pwd)"
v_echo "---"
v_echo "TODO:        ${todo:=default}"

v_var todo

# Do some work...
rc=0


# Exit with the return code...
exit $rc