bash设置代理脚本

Question

下面是我设置代理的bash脚本，我绝不是bash的专家。我怀疑有更好的方式来写这个，任何提示都会受到赞赏。

添加更多详细信息以满足stackoverflows要求。有没有更好的方法来执行嵌套的while循环和if语句？

#!/bin/bash
set -e    

#functions
function yesno() {
  while read -n1 -r -p "[y/n/QUIT] > "; do
    case $REPLY in
      y|n) return;;
      q) echo; echo; exit 1;;
      *) printf "\nERROR - Invalid response, please enter Yes OR No.\n";;
    esac
  done
}

function startover() {
  printf "\n\n\e[1m\e[31mStarting Over...\e[0m\n"
  sleep 2
  unset proxyport proxyhost
}


    shopt -s nocasematch
    while true; do
      printf "\nIs a proxy required to access outbound \e[1m\e[7mHTTP/HTTPS\e[0m sites?\n"
      yesno
      if [[ $REPLY == "y" ]]; then
        printf "\n\nPlease enter your proxy url\nExample - \e[1m\e[7mproxy.example.com:8080\e[0m\n"
        while read -r -p "Proxy > " proxy; do
          if [[ $proxy =~ ^https:// && $proxy =~ :[0-9]{1,5}$ ]]; then
            printf "\nERROR - HTTPS with a port is not supported, please re-enter without '\e[1m\e[97m\e[41mHTTPS://\e[0m' prefix\n"
          elif [[ $proxy =~ ^(https?://)?([a-z0-9][-a-z0-9\.]{0,61}[a-z0-9]\.[a-z]{2,5})?.((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))?(:[0-9]{1,5})?$ ]]; then
            if [[ $proxy =~ :[0-9]{1,5}$ ]]; then
              proxyport=${proxy##*:}
              proxy=${proxy%:*}
              echo "Port entered $proxyport"
            elif [[ $proxy =~ ^https:// && ! $proxy =~ :[0-9]{1,5}$ ]]; then
              proxyport=443
              echo "URL starts with HTTPS, assuming $proxyport"
            else
              proxyport=80
              echo "No port entered, assuming $proxyport"
            fi
            proxyhost=${proxy##*/}
            break
          else
            printf "\nERROR - \e[1m\e[97m\e[41m$proxy\e[0m is not supported please try again\n"
          fi
        done
        printf "\nCreating Proxy Settings\n"
        sleep 2
        printf "Proxy Hostname: \e[1m\e[97m\e[44m$proxyhost\e[0m\nProxy Port: \e[1m\e[97m\e[44m$proxyport\e[0m\nDoes the information above look correct?\n"
        yesno
        if [[ $REPLY == "n" ]]; then
          startover
        fi
      fi
      break
    done
    shopt -u nocasematch