title: unexpected EOF while looking for matching `' '
body: <pre><code>#!/usr/bin/perl
  use warnings;
  while(1){
  system ( "dialog --menu Customize 30 80 60 "
          . "'Show rules' 'Show all the current rules' "
          . "'Flush rules' 'Flush all the tables' "
      . "Allow IP' 'Block all except one IP' "
      . "'Block IP' 'Block all the packets from an IP' "
      . "'Block MAC' 'Block using the hardware address' "
          . "'Private networking' 'Allow only one network and block other networks' "
      . "'Allow lo' 'Allow local network interface' "
      . "'Save' 'Save customized rules' "
      . "'Exit' 'Close the program' "
          . "'more options' '........' 2&gt; /tmp/customize.txt");
  
  open FILE4, "/tmp/customize.txt" or die $!;
  chomp(my $customize = &lt;FILE4&gt;);
          #SHOW RULES
                  if($customize =~ /Show rules/){
          `iptables -nvL | tee /tmp/nvl.txt`;
                  system ("dialog --textbox /tmp/nvl.txt 22 70");
                  }
          #FLUSH RULES
          elsif($customize =~ /Flush rules/){
          `iptables -F`;
          system ("dialog --infobox 'All tables have been flushed.' 05 35");
          sleep 2;
          }
          #ALLOW IP
          elsif($customize =~ /Allow IP/){
          system ("dialog --inputbox 'Enter the IP address of the sysetm which you want to allow:' 15 40 2&gt; /tmp/allowIP.txt");
          open FILE7, "/tmp/allowIP.txt" or die $!;
          chomp(my $aip = &lt;FILE7&gt;);
          `iptables -I INPUT -s $aip -j DROP`;
          system ("dialog --infobox 'IP address $aip is allowed and rest are blocked' 05 45");
          sleep 2;
          }
          #BLOCK IP
          elsif($customize =~ /Block IP/){
          system ("dialog --inputbox 'Enter the IP address of the system which you want to block:' 15 40 2&gt; /tmp/blockIP.txt");
          open FILE5, "/tmp/blockIP.txt" or die $!;
          chomp(my $ip = &lt;FILE5&gt;);
          `iptables -A INPUT -s $ip -j DROP`;
          system ("dialog --infobox 'IP address $ip has been blocked!' 05 35");
          sleep 2;
          }
          #PRIVATE NETWORK    
          elsif($customize =~ /Private networking/){
          system ("dialog --inputbox 'Enter the network address which you want to allow (eg. 192.168.0.0/24)' 15 40 2&gt; /tmp/network.txt");
          open FILE6, "/tmp/network.txt" or die $!;
          chomp(my $network = &lt;FILE6&gt;);
          `iptables -I INPUT -s $network -j ACCEPT`;
          system ("dialog --infobox 'Network $network is allowed and rest networks are blocked' 05 35");
          sleep 2;
          }
          #ALLOW LO
          elsif($customize =~ /Allow lo/){
          `iptables -I INPUT -i lo -j ACCEPT`;
          system ("dialog --infobox 'Local interface is allowed.' 05 35");
          sleep 2;
          }
          #SAVE
          elsif($customize =~ /Save/){
          `service iptables save`;
          system ("dialog --infobox 'All rules have been saved successfully' 05 45");
          sleep 2;
          }
          #EXIT
          elsif($customize =~ /Exit/){
          system ("dialog --infobox 'Closing application.' 05 35");
          sleep 2;
          exit 0;
          }
                  else{
                          exit;
                  }
  }
  </code></pre>
  
  <blockquote>
    <p>perl file.plx</p>
  </blockquote>
  
  <p><strong>error</strong>: </p>
  
  <pre><code>sh: -c: line 0: unexpected EOF while looking for matching `'' 
  sh: -c: line 1: syntax error: unexpected end of file
  </code></pre>
  
  <p>How do I resolve this error?</p>