https://natelandau.com/bash-scripting-utilities/

utils.sh

#!/bin/bash
# https://natelandau.com/bash-scripting-utilities/

#
# Set Colors
#

bold=$(tput bold)
underline=$(tput sgr 0 1)
reset=$(tput sgr0)

purple=$(tput setaf 171)
red=$(tput setaf 1)
green=$(tput setaf 76)
tan=$(tput setaf 3)
blue=$(tput setaf 38)

#
# Headers and  Logging
#

e_header() { printf "\n${bold}${purple}==========  %s  ==========${reset}\n" "$@"
}
e_arrow() { printf "➜ $@\n"
}
e_success() { printf "${green}✔ %s${reset}\n" "$@"
}
e_error() { printf "${red}✖ %s${reset}\n" "$@"
}
e_warning() { printf "${tan}➜ %s${reset}\n" "$@"
}
e_underline() { printf "${underline}${bold}%s${reset}\n" "$@"
}
e_bold() { printf "${bold}%s${reset}\n" "$@"
}
e_note() { printf "${underline}${bold}${blue}Note:${reset}  ${blue}%s${reset}\n" "$@"
}

#
# USAGE FOR SEEKING CONFIRMATION
# seek_confirmation "Ask a question"
# Credt: https://github.com/kevva/dotfiles
#
# if is_confirmed; then
#   some action
# else
#   some other action
# fi
#

seek_confirmation() {
  printf "\n${bold}$@${reset}"
  read -p " (y/n) " -n 1
  printf "\n"
}

# underlined
seek_confirmation_head() {
  printf "\n${underline}${bold}$@${reset}"
  read -p "${underline}${bold} (y/n)${reset} " -n 1
  printf "\n"
}

# Test whether the result of an 'ask' is a confirmation
is_confirmed() {
if [[ "$REPLY" =~ ^[Yy]$ ]]; then
  return 0
fi
return 1
}

#
# Test whether a command exists
# $1 = cmd to test
# Usage:
# if type_exists 'git'; then
#   some action
# else
#   some other action
# fi
#

type_exists() {
if [ $(type -P $1) ]; then
  return 0
fi
return 1
}

#
# Test which OS the user runs
# $1 = OS to test
# Usage: if is_os 'darwin'; then
#

is_os() {
if [[ "${OSTYPE}" == $1* ]]; then
  return 0
fi
return 1
}

#
# Pushover Notifications
# Usage: pushover "Title Goes Here" "Message Goes Here"
# Credit: http://ryonsherman.blogspot.com/2012/10/shell-script-to-send-pushover.html
#

pushover () {
    PUSHOVERURL="https://api.pushover.net/1/messages.json"
  API_KEY="your-api-here"
  USER_KEY="your-user-key-here"
    DEVICE=""

    TITLE="${1}"
    MESSAGE="${2}"

    curl \
    -F "token=${API_KEY}" \
    -F "user=${USER_KEY}" \
    -F "device=${DEVICE}" \
    -F "title=${TITLE}" \
    -F "message=${MESSAGE}" \
    "${PUSHOVERURL}" > /dev/null 2>&1
}

#
# Given a list of desired items and installed items, return a list
# of uninstalled items. Arrays in bash are insane (not in a good way).
# Credit: https://github.com/cowboy/dotfiles
#

function to_install() {
  local debug desired installed i desired_s installed_s remain
  if [[ "$1" == 1 ]]; then debug=1; shift; fi
    # Convert args to arrays, handling both space- and newline-separated lists.
    read -ra desired < <(echo "$1" | tr '\n' ' ')
    read -ra installed < <(echo "$2" | tr '\n' ' ')
    # Sort desired and installed arrays.
    unset i; while read -r; do desired_s[i++]=$REPLY; done < <(
      printf "%s\n" "${desired[@]}" | sort
    )
    unset i; while read -r; do installed_s[i++]=$REPLY; done < <(
      printf "%s\n" "${installed[@]}" | sort
    )
    # Get the difference. comm is awesome.
    unset i; while read -r; do remain[i++]=$REPLY; done < <(
      comm -13 <(printf "%s\n" "${installed_s[@]}") <(printf "%s\n" "${desired_s[@]}")
  )
  [[ "$debug" ]] && for v in desired desired_s installed installed_s remain; do
    echo "$v ($(eval echo "\${#$v[*]}")) $(eval echo "\${$v[*]}")"
  done
  echo "${remain[@]}"
}