title: failed to use iconv to change encoding in shell
body: <p>I have a file to convert its encoding.
  In terminal, I have :</p>
  
  <pre><code>$file -i *
  </code></pre>
  
  <p>and it turns out <code>text/plain; charset=us-ascii</code></p>
  
  <p>Then I have this command line :</p>
  
  <pre><code>$ iconv -f us-ascii -t UTF-8 oldfile.txt &gt; newfile.txt
  </code></pre>
  
  <p>It turns out a message: <code>iconv: illegal input sequence at position 2575661</code> </p>
  
  <p>I searched and found that this suggests there are invalid sequences (for instance this page <a href="https://spin.atomicobject.com/2011/07/13/some-useful-iconv-functionality/" rel="nofollow">https://spin.atomicobject.com/2011/07/13/some-useful-iconv-functionality/</a>). I am wondering what would be the most reliable way to convert the encoding to the most appropriate encoding to sqlite, and how to find the invalid sequences? Thank you!!</p>