Script that will update system autoconf to the desire version as alternatives

update-autoconf.sh

#!/bin/bash
set -e

WHAT=autoconf
VERSION=2.71
FULLNAME=${WHAT}-${VERSION}
INSTDIR=/opt/${FULLNAME}

function install() {
    [ $# -eq 0 ] && { run_error "Usage: install <version>"; exit; }
    local VERSION=${1}
    local TARBALL=${FULLNAME}.tar.xz
    local URL=ftp://ftp.gnu.org/gnu/${WHAT}/${TARBALL}
    local WHERE=/tmp/update-${WHAT}
    mkdir -p ${WHERE}
    cd ${WHERE}
    echo "Downloading ${URL}"
    curl -L --create-dirs -o ${TARBALL} ${URL}

    if [ -f "${TARBALL}" ]; then
        tar -xf ${TARBALL}
        cd ${FULLNAME}
        ./configure --prefix=${INSTDIR}
        make
        echo "Installing..."
        sudo make install
        echo -e "${TARBALL} installed \e[1;32mOK\e[39m"
    else
        echo -e "Cannot download ${URL}"
        exit 1
    fi
}

function install_alternatives() {
    for fullpath in ${INSTDIR}/bin/* ; do
        local NAME="$(basename ${fullpath})"
        #echo "sudo update-alternatives --install /usr/local/bin/${NAME} ${NAME} ${fullpath} 50"
        sudo update-alternatives --install /usr/local/bin/${NAME} ${NAME} ${fullpath} 50        
    done

    # https://superuser.com/a/1086506/459389
    sudo ln -sf ${INSTDIR}/share/autoconf /usr/share/${FULLNAME}
    . ~/.profile
}

function remove_alternatives() {
    for fullpath in ${INSTDIR}/bin/* ; do
        local NAME="$(basename ${fullpath})"
        #echo "sudo update-alternatives --remove ${NAME} ${fullpath}"
        sudo update-alternatives --remove ${NAME} ${fullpath}
    done

    sudo rm /usr/share/${FULLNAME}
    . ~/.profile
}

if declare -f "$1" > /dev/null
then
    "$@"
else
    install ${VERSION}
    install_alternatives
fi