general

#!/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

# -----------------------------------------------------------------------------
# Copyright (C) Business Learning Incorporated (businesslearninginc.com)
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation, either version 3 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License at
# <http://www.gnu.org/licenses/> for more details.
#
# -----------------------------------------------------------------------------
#
# bash library for general-purpose script processing
#

# -----------------------------------------------------------------------------
# check_program_dependencies() checks external program dependencies passed in
# through $0
#
function check_program_dependencies() {

  local -a deps=("$@")

  for i in "${deps[@]}"; do

    if ! command -v "$i" &>/dev/null; then
      printf "\n%s\n" "Error: program $i not installed."
      quit 1
    fi

  done

}

# -----------------------------------------------------------------------------
# check_file_dependencies() checks file dependencies passed in through $0
#
function check_file_dependencies() {

  local -a deps=("$@")

  for i in "${deps[@]}"; do

    if [ ! -f "$i" ]; then
      printf "\n%s\n" "Error: file $i not found."
      quit 1
    fi

  done

}

# -----------------------------------------------------------------------------
# display_banner() builds and displays a custom-sized script banner using
# configuration details managed through the args library
#
function display_banner() {

  printf "\n"
  printf "%s\n" " |"
  printf "%s\n" " |  $(get_config_details title)"
  printf "%s\n" " |    $(get_config_details version)"
  printf "%s\n" " |"
  printf "%s\n" " |  Usage:"
  printf "%s\n" " |    $(get_config_details syntax)"
  printf "%s\n" " |"

  local max_col=0
  local count_args=0
  count_args=$(get_config_args_length)

  # determine maximum column width for setting output columns
  #
  for ((j = 0; j < count_args; j++)); do
    arg_len=$(get_config_arg "$j" short_form)+$(get_config_arg "$j" long_form)
    ((${#arg_len} > max_col)) && max_col=${#arg_len}
    ((j == count_args - 1)) && ((max_col += 6))
  done

  for ((j = 0; j < count_args; j++)); do
    printf "%-${max_col}s %s\n" " |  $(get_config_arg "$j" short_form), $(get_config_arg "$j" long_form)" "$(get_config_arg "$j" description)"
  done

  printf "%s\n\n" " |"

}

# -----------------------------------------------------------------------------
# function exist_directory() confirms directory existence
#
function exist_directory() {

  if [ ! -d "${1}" ]; then
    printf "\n%s\n" "Error: directory ${1} not found."
    quit 1
  fi

}

# -----------------------------------------------------------------------------
# quit() exits program (with exit status passed in)
#
function quit() {

  local result=""
  result=("${1}")

  printf "\n"
  exit "${result[0]}"

}