Installing Bash on Ubuntu / Centos / Alpine with --enable-net-redirections

install_bash.sh

#!/usr/bin/env sh

LINUX_DISTRO="$(. /etc/os-release ; echo ${ID})"
BASH_VERSION="bash-5.0"
SOURCE_DIR="/var/opt/"

prereqs_centos(){
  install_bash
  yum install -y -q gcc make &> /dev/null
  yum clean all &> /dev/null
  rm -rf /var/cache/yum/
}

prereqs_ubuntu(){
  install_bash
  apt-get update &> /dev/null
  apt-get -y install gcc make &> /dev/null
  ./configure --enable-net-redirections
}

prereqs_alpine(){
  install_bash
  apk add --no-cache gcc g++ make &> /dev/null
}

install_bash(){
  cd "${SOURCE_DIR}/${BASH_VERSION}"
  ./configure --enable-net-redirections ${1}
  make
  make test
  make install
  /usr/local/bin/bash --version
}

case "${LINUX_DISTRO}" in
  alpine)
    prereqs_alpine
    wget -q "http://git.savannah.gnu.org/cgit/bash.git/snapshot/${BASH_VERSION}.tar.gz" -O- | tar -xz -C "${SOURCE_DIR}"
    install_bash --without-bash-malloc
    ;;
  centos)
    prereqs_centos
    curl -sL "http://git.savannah.gnu.org/cgit/bash.git/snapshot/${BASH_VERSION}.tar.gz" | tar -xz -C "${SOURCE_DIR}"
    install_bash
    ;;
  ubuntu)
    prereqs_ubuntu
    curl -sL "http://git.savannah.gnu.org/cgit/bash.git/snapshot/${BASH_VERSION}.tar.gz" | tar -xz -C "${SOURCE_DIR}"
    install_bash
    ;;
  *)
    echo "${LINUX_DISTRO} is not supported"
    ;;
esac

I believe sh has case statements. Is there a reason why you used if-elif instead of case statements? That would optimize ( minor, but still ) to only one comparison compared to 3 ( at worst ).

Also, a cool trick I learned ( by I think reading digitalocean's logging script ) about the /etc/*release files is that you can source those files and then just echo/printf that variable. Because they are all in variable assignment format, so instead of parsing for it just do something like LINUX_DISTRO="$(source /etc/*release ; echo "${ID}" )"

Since that is a subshell no variables should be introduced to your script ( IIRC ), and you don't have to parse anything out + echo/printf are builtins ( as well as source ( or the alias of . if you want to be minimal ) ).