A simple tool to download and use the latest Maven version

update-maven.sh

#! /usr/bin/bash

set -e

cd "$(dirname "$0")"

# check if running in a color terminal
terminalSupportsColor() {
  local c
  c=$(tput colors 2>/dev/null) || c=-1
  [[ -t 1 ]] && [[ $c -ge 8 ]]
}
terminalSupportsColor && doColor=1 || doColor=0

color() {
  local c
  c=$1
  shift
  [[ $doColor -eq 1 ]] && echo -e "\\e[0;${c}m${*}\\e[0m" || echo "$@"
}
red() { color 31 "$@"; }
green() { color 32 "$@"; }
yellow() { color 33 "$@"; }

fail() {
  echo -e ' ' "$@"
  exit 1
}
run() { echo "$(green Running) $(yellow "$@")" && "$@"; }

updateMaven() {
  local ver=$1
  local dir="apache-maven-$ver"
  local file="$dir-bin.tar.gz"
  local url="https://dlcdn.apache.org/maven/maven-3/$ver/binaries"
  if [[ -z $ver ]]; then
    fail "Version is $(red missing)"
  elif ! [[ $ver =~ ^[34][.][1-9][0-9]*[.][1-9][0-9]*$ ]]; then
    fail "Version $(red "$ver") is not recognized"
  fi
  run wget -c "$url/$file" -O "$file"
  run wget "$url/$file.sha512" -O "$file.sha512"
  run wget "$url/$file.asc" -O "$file.asc"
  echo "$(green Adding) filename $(yellow "$file") to raw hash in $(red "$file.sha512")"
  echo "  $file" >>"$file.sha512"
  run shasum -c "$file.sha512"
  run gpg --verify "$file.asc" "$file"
  run tar xf "$file"
  run ln -sdfT "$dir" current
  run ls --color=always --classify=always -ald current
}

updateMaven "$@"