Writes a multi-distro install pre-requs script

scripts/installs/prerequisites.sh

@@ -0,0 +1,96 @@
+#!/usr/bin/env bash
+
+######################################################################
+# Core Dependency Install Script                                     #
+######################################################################
+# Installs essential pre-requsite packages, when using new systems   #
+# Intended to be run before install.sh, if packages not yet present. #
+# All other package inatslls are managed in system-specific scripts  #
+# For docs and more info, see: https://github.com/lissy93/dotfiles   #
+# IMPORTANT: Before running, read through everything very carefully! #
+######################################################################
+# Licensed under MIT (C) Alicia Sykes 2022 <https://aliciasykes.com> #
+######################################################################
+
+# List of apps to install
+core_packages=(
+  'git' # Needed to fetch dotfiles
+  'vim' # Needed to edit files
+  'zsh' # Needed as bash is crap
+)
+
+# Color variables
+PURPLE='\033[0;35m'
+YELLOW='\033[0;93m'
+LIGHT='\x1b[2m'
+RESET='\033[0m'
+
+# Shows help menu / introduction
+function print_usage () {
+  echo -e "${PURPLE}Prerequisite Dependency Installation Script${LIGHT}\n"\
+  "There's a few packages that are needed in order to continue with setting up dotfiles.\n"\
+  "This script will detect distro, and use appropriate package manager to install apps.\n"\
+  "Elavated permissions may be required. Ensure you've read the script before proceeding."\
+  "\n${RESET}"
+}
+
+function install_debian () {
+  echo -e "${PURPLE}Installing ${1} via apt-get${RESET}"
+  sudo apt install $1
+}
+function install_arch () {
+  echo -e "${PURPLE}Installing ${1} via Pacman${RESET}"
+  sudo pacman -S $1
+}
+function install_mac () {
+  echo -e "${PURPLE}Installing ${1} via Homebrew${RESET}"
+  brew install $1
+}
+function get_homebrew () {
+  echo -e "${PURPLE}Setting up Homebrew${RESET}"
+  /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+  export PATH=/opt/homebrew/bin:$PATH
+}
+
+# Detect OS type, then triggers install using appropriate package manager
+function multi_system_install () {
+  app=$1
+  if [ "$(uname -s)" = "Darwin" ]; then
+    if ! hash brew 2> /dev/null; then get_homebrew; fi
+    install_mac $app # MacOS via Homebrew
+  elif [ -f "/etc/arch-release" ] && hash pacman 2> /dev/null; then 
+    install_arch $app # Arch Linux via Pacman
+  elif ! [ -f "/etc/debian_version" ] && hash apt 2> /dev/null; then
+    install_debian $app # Debian via apt-get
+  else
+    echo -e "${YELLOW}Skipping ${app}, as couldn't detect system type ${RESET}"
+  fi
+}
+
+# Show usage instructions, help menu
+print_usage
+if [[ $* == *"--help"* ]]; then exit; fi
+
+# Ask user if they'd like to proceed
+if [[ ! $* == *"--auto-yes"* ]] ; then
+  echo -e "${PURPLE}Are you happy to continue? (y/N)${RESET}"
+  read -t 15 -n 1 -r
+  echo
+  if [[ ! $REPLY =~ ^[Yy]$ ]]; then
+    echo -e "${YELLOW}Proceeding was rejected by user, exiting...${RESET}"
+    exit 0
+  fi
+fi
+
+# For each app, check if not present and install
+for app in ${core_packages[@]}; do
+  if ! hash "${app}" 2> /dev/null; then
+    multi_system_install $app
+  else
+    echo -e "${YELLOW}${app} is already installed, skipping${RESET}"
+  fi
+done
+
+# All done
+echo -e "\n${PURPLE}Jobs complete, exiting${RESET}"
+exit 0