bash_helpers.sh

#!/usr/bin/env bash

# @help     Write an error message and exit.
# @usage    error <message>
error() {
  local message=$1; shift;
  printf "\e[01;31merror: $message\e[0m\n" >&2;
  exit 1;
}

# @help     Output piped to this function is formatted and printed.
# @usage    wrap_out <lines..>
wrap_out() {
  while read line; do
    echo "  > $line"
  done
}

# @help     Output piped to this function is formatted and printed.
# @usage    wrap_err <lines...>
wrap_err() {
  while read line; do
    printf "\e[01;31m  > $line\e[0m\n" >&2
  done
}

# @help     Run any command and format output.
# @usage    cmd <command>
cmd() {
  echo
  echo "  # $@"
  (cd "$PWD" && (eval $@) 2>&1 1>&3 3>&- | wrap_err) 3>&1 1>&2 | wrap_out
  echo
}

# @help     Run any command from the PROJECT_PATH
#           directory and format output.
# @return   cmdcd <command>
cmdcd() {
  local path=$1; shift

  echo
  echo "  # $@"
  (cd "$path" && (eval $@) 2>&1 1>&3 3>&- | wrap_err) 3>&1 1>&2 | wrap_out
  echo
}

# @help     Return absolute path of a file or directory.
# @usage    realpath <path>
# @return   absolute file path
realpath() {
  [[ $1 = /* ]] && echo "$1" || echo "$PWD/${1#./}"
}

# @help     Prompts user for input and writes answer in
#           to the target variable. Will not prompt if
#           INTERACTIVE has been disabled. If the target
#           already contains either "y" or "n", then that
#           value is used. If the DEFAULT_ANSWER is defined,
#           then this value is used as the answer. Otherwise
#           user is prompted for input.
# @usage    ask <question> <answer>
ask() {
  local question="$1"
  local answer="$2"

  # ${!...} is used to retrieve a value
  # trough the variable name (indirect expansion)
  case ${!answer} in
    y|n);;
    *)
      if [[ "$DEFAULT_ANSWER" ]]; then
        eval "$answer=$DEFAULT_ANSWER"
        return
      fi

      if [[ "$INTERACTIVE" == "y" ]]; then
        read -p "$question" $answer
        return
      fi
    ;;
  esac
}

# @help     Prompts user for input and writes answer in
#           to the target variable. Will not prompt if
#           INTERACTIVE has been disabled. If the target
#           already contains either "y" or "n", then that
#           value is used. Otherwise user is prompted for
#           input.
# @usage    ask <question> <answer>
prompt() {
  local question="$1"
  local answer="$2"

  # ${!...} is used to retrieve a value
  # trough the variable name (indirect expansion)
  if [[ ! ${!answer} && "$INTERACTIVE" == "y" ]]; then
    read -p "$question" "$answer"
    return
  fi
}