title: grep -v -f not working
body: <p>So I am trying to use</p>
  
  <pre><code>grep -v -f A.txt  B.txt
  </code></pre>
  
  <p>to display lines NOT included in file A but present in file B. When I</p>
  
  <pre><code>grep -f A.txt B.txt
  </code></pre>
  
  <p>everything works fine I receive output with correct lines highlighted, but when I use</p>
  
  <pre><code>grep -v -f A.txt B.txt
  </code></pre>
  
  <p>nothing is outputted in spite of the fact that not all lines match patterns. Does anyone knows why? I am interested in seeing lines NOT present in file A.</p>
  
  <p>Note: I am including just a sample of original file but it includes all troublesome lines.</p>
  
  <p>file B.txt contents:</p>
  
  <pre><code>/lgi/tch/4337984048.html
  /mnh/tch/4337954734.html
  /fct/tch/4337745272.html
  /brk/tch/4337711890.html
  /mnh/tch/4337530587.html
  /mnh/tch/4337480118.html
  /mnh/tch/4337393833.html
  /wch/tch/4337280071.html
  /wch/tch/4337105236.html
  /brk/tch/4337068170.html
  </code></pre>
  
  <p></p>
  file A.txt contents: </p></p>
  
  <pre><code>/mnh/tch/4337480118.html
  /mnh/tch/4337393833.html
  /wch/tch/4337280071.html
  /wch/tch/4337105236.html
  /brk/tch/4337068170.html
  </code></pre>