title: having an issue with my bash script
body: <p>im writing a script that allows the user to create a backup of a file they choose by allowing them to input the file name. the file will then have backup followed by being date stamped at the end of it's name and saved on the home drive. but whenever i try to run it i get an error: cp: missing destination file operand after '_backup_2017_12_16'</p>
  
  <p>here's my code:</p>
  
  <pre><code>title="my script 3" 
  prompt="Enter:"        
  options=("create a backup of a file")  
  echo "$title"
  PS3="$prompt "
  select opt in "${options[@]}" "Quit"; do 
  
      case "$REPLY" in
  esac
      cp "$filename""${file}_backup_$(date +%Y_%m_%d)"
  done
  </code></pre>