Use rbenv to automate updating to latest ruby version

updateRuby

#!/bin/bash
# Name: updateRuby
# Purpose: Upgrade ruby
# Author: Privat Krish Mamtora Atmaram
# -----------------------------------------------------------------------------------

usage ()
{
cat <<EOF

Update ruby version (using rbenv)
USAGE: updateRuby

EOF
exit 1;
}

if [ "$#" -ge 1 ]
then
  usage
fi


command -v rbenv >/dev/null 2>&1 || { echo >&2 "rbenv is not installed. Aborting."; exit 1; }
command -v ruby-build >/dev/null 2>&1 || { echo >&2 "ruby-build is not installed. Aborting."; exit 1; }

current=$(rbenv version | xargs)
if [[ "$current" =~ ^\(.*\)$ ]] ;
  then
    # This situation happens when something was uninstalled and global is set to a non-existant package
    current="";
  else

    current=$(echo "$current" | cut -d " " -f 1);
fi

# Handel situation for when using system version
if [ "$current" == "system" ] ;
  then
    current=""
fi

available="$(rbenv install -l | tail -n +2  | awk '{$1=$1};1')";

if [[ ${current:0:1} =~ [[:alpha:]] ]] ;
  then
    type="$(echo "$current" | xargs | cut -d "-" -f 1)";
    ver="$(echo "$available" | grep "^[^0-9].*" | grep "^$type.*" | cut -d "-" -f 2 | grep -v "[^\.0-9]" | tail -1)";
    latest="$(echo "$type-$ver")";
  else
    latest="$(echo "$available" | grep "^[^a-zA-Z].*" | grep -v "[-]\+" | tail -1)";
fi
installed=$(rbenv versions | sed "/$latest/! d" | xargs | cut -d " " -f 2)


echo "Current: $current";
echo "Latest: $latest";
echo "Installed: $installed";

#Situations
#If no current > Get latest
#If not using latest and it is already installed  > switch to latest
#If latest not installed and not current > install latest, switch to it, remove current

if [ "$latest" == "$current" ]
  then
    echo "Already have latest"
elif [ "$latest" != "$current" ] && [ "$latest" == "$installed" ]
  then
    echo "Have latest, switching to $latest"
    eval "rbenv global $latest"
elif [ "$latest" != "$current" ] && [ "$latest" != "$installed" ]
  then
    if [ "$current" == "" ] ;
      then
        echo "Don't have latest, installing $latest"
        eval "rbenv install $latest" && eval "rbenv global $latest"
    else
        echo "Dont have latest, installing $latest, removing $current"
        eval "rbenv install $latest" && eval "rbenv global $latest" && eval "rbenv uninstall $current" <<< "y"
    fi
fi

Manage when current version is system

Can you update this to reinstall all existing gems from the current to the latest? Seems like reinstalling is preferred over copying