title: How to grep rows that have value less than or equal to value
body: <pre><code>size=139
  size=9292
  size=140
  size=139
  size=139
  size=10213
  size=139
  size=140
  size=11186
  size=139
  size=139
  size=140
  size=12342
  size=139
  size=139
  size=140
  size=11360
  </code></pre>
  
  <p>How can I grep rows that has greater value than 1000 from size.txt ?</p>
  
  <p>Also, is there any way that I could find this information from entire folder, which has many txt files like this  ?</p>