Install the latest version of Apache Maven on Ubuntu

install-maven.sh

#! /usr/bin/env bash
#
# [ install-maven.sh ]
#
#    Install Apache Maven on Ubuntu
#
#    Created on 20200830 by h8rt3rmin8r (161803398@email.tg)
#
#  Reference:
#
#    https://maven.apache.org/download.cgi
#    https://linuxize.com/post/how-to-install-apache-maven-on-ubuntu-20-04/
#
#  Source:
#
#    http://bit.ly/github-install-maven
#    http://bit.ly/github-install-maven-raw
#    http://bit.ly/pastebin-install-maven
#    http://bit.ly/pastebin-install-maven-raw
#
#-------------------------------------------------------------------------------
# Declare functions

function imaven_cleanup() {
    # Remove downloaded file from /tmp

    rm "${lm_filepath}" &>/dev/null

    return $?
}

function imaven_download() {
    # Download the latest version of Maven

    wget --show-progress "${lm_link}" -P /tmp

    return $?
}

function imaven_environment() {
    # Write environment variables script for Maven

    local out_file="/etc/profile.d/maven.sh"

    sudo echo '#! /usr/bin/env bash' > "${out_file}"
    sudo echo '#' >> "${out_file}"
    sudo echo '# [ maven.sh ]' >> "${out_file}"
    sudo echo '#' >> "${out_file}"
    sudo echo "#    Established on $(date '+%Y-%m-%d %H:%M:%S') by $(whoami)" >> "${out_file}"
    sudo echo '#' >> "${out_file}"
    sudo echo "" >> "${out_file}"
    sudo echo 'export JAVA_HOME=/usr/lib/jvm/default-java' >> "${out_file}"
    sudo echo 'export M2_HOME=/opt/maven' >> "${out_file}"
    sudo echo 'export MAVEN_HOME=/opt/maven' >> "${out_file}"
    sudo echo 'export PATH=${M2_HOME}/bin:${PATH}' >> "${out_file}"
    sudo echo "" >> "${out_file}"

    sudo chmod +x /etc/profile.d/maven.sh

    return $?
}

function imaven_extract() {
    # Extract the downloaded Maven source code

    sudo tar xf "${lm_filepath}" -C /opt

    return $?
}

function imaven_latestversion() {
    # Look for the latest version of Maven
    curl -s 'https://maven.apache.org/download.cgi' \
        | grep -E '<h2.*h2>' \
        | sed 's/^.*Maven\ //;s/<.*//'

    return $?
}

function imaven_softcheck() {
    # Check for the existance of an input software on the local system

    local i_n="${1}"

    if [[ "x${i_n}" == "x" ]]; then
        imaven_vb -e "Encountered an internal error: ${FUNCNAME}"
        
        return 1
    fi

    ${i_n} -version &>/dev/null
    local e_c="$?"

    return ${e_c}
}

function imaven_symlink() {
    # Create a symbolic link to the latest version of Maven

    sudo ln -s "/opt/apache-maven-${lm_version}" /opt/maven

    return $?
}

function imaven_vb() {
    # Verbosity handler

    if [[ "${1}" =~ ^[-]+[eisw]$ ]]; then
        local vb_type_pre="${1//[-]}"
        local vb_type="${vb_type_pre^^}"
    else
        local vb_type="I"
    fi

    local vb_message="$@"
    local vb_timestamp="$(date '+%s.%N')"
    local vb_output="${vb_timestamp}|${vb_type}|${sh_name}|${vb_message}"

    echo "${vb_output}" &>/dev/stderr

    return $?
}

#-------------------------------------------------------------------------------
# Declare variables

sh_name="${0//*\/}"
lm_version=$(imaven_latestversion)
lm_build="${lm_version//[.]*}"
lm_domain="https://www-us.apache.org"
lm_file="apache-maven-${lm_version}-bin.tar.gz"
lm_filepath="/tmp/${lm_file}"
lm_linkpath="/dist/maven/maven-${lm_build}/${lm_version}/binaries/${lm_file}"
lm_link="${lm_domain}${lm_linkpath}"
soft_check_a=$(imaven_softcheck "java")
soft_check_b=$(imaven_softcheck "mvn")

#-------------------------------------------------------------------------------
# Execute operations

imaven_vb -i "Beginning Maven installation process ..."

## Make sure the latest version of Maven was found on the remote host

if [[ "x${lm_version}" == "x" || "x${lm_build}" == "x" ]]; then
    imaven_vb -e "Unable to determine the latest version of Maven"
    imaven_vb -i "Check your Internet connection and try again"

    exit 1
else
    imaven_vb -i "Discovered latest Maven version: ${lm_version}"
fi

## Check if Maven is already installed on the local system

if [[ "${soft_check_b}" -eq 0 ]]; then
    imaven_vb -e "Maven is already installed on the local system"
    imaven_vb -e "Terminating installation processes"

    exit 1
fi

## Update the local package list

imaven_vb -i "Updating the local package list (requires sudo)"

sudo apt update

## If JDK isn't installed, kick off the installation

if [[ "${soft_check_a}" -ne 0 ]]; then
    imaven_vb -w "Required software 'default-jdk' not found"
    imaven_vb -i "Installing 'default-jdk' (requires sudo)"

    sudo apt install default-jdk
fi

## Download the latest Maven source code

imaven_download

## Extract the download into the '/opt' directory and delete the tmp file

imaven_extract
imaven_cleanup

## Create a symbolic link for the latest version of Maven

imaven_symlink

## Build environment variables script for Maven

imaven_environment

## Source the environment variables script

source /etc/profile.d/maven.sh

## Verify the installation process was completed successfully

soft_check_b=$(imaven_softcheck "mvn")

if [[ "${soft_check_b}" -ne 0 ]]; then
    imaven_vb -e "An unknown error has occurred; installation may be corrupt"
    imaven_vb -e "Terminating installation processes"

    exit 1
else
    imaven_vb -s "Installation of Maven version ${lm_version} is COMPLETE"
    imaven_vb -i "IMPORTANT NOTE: Add the following line to ${HOME}/.bashrc:"
    echo 'source /etc/profile.d/maven.sh' &>/dev/stderr

    exit 0
fi