<div id="app">
  <h1> Tool: Remove Duplicate Lines</h1>
  <div style="padding:4px 0px 7px 0px;">
    <button @click="rduplin">Remove Duplicate Lines</button>
    <input type="checkbox" v-model="case_sen" >Case sensitive.
    <input type="checkbox" v-model="rel" >Remove empty lines.
    <input type="checkbox" v-model="dis_rem">Display removed.
    <span id="removed">{{removed}}</span>
  </div>
  <textarea v-model="input_output" style="width:100%;" rows="4" wrap="off"></textarea>
  <div v-if="dis_rem" style="padding-top:10px;">
    <textarea v-model="removed_output" rows="4" style="width:100%;" wrap="off"></textarea>
  </div>