title: grep/regex can't find accented word
body: <p>I'm trying mount a regex that get some words on a file where all letters of this word match with a word pattern.</p>
  
  <p>My problem is, the regex can't find accented words, but in my text file there are alot of accented words.</p>
  
  <p>My command line is:</p>
  
  <pre><code>cat input/words.txt | grep '^[éra]\{1,4\}$' &gt; output/words_era.txt
  cat input/words.txt | grep '^[carroça]\{1,7\}$' &gt; output/words_carroca.txt
  </code></pre>
  
  <p>And the content of file is: </p>
  
  <pre><code>carroça
  éra
  éssa
  roça
  roco
  rato
  onça
  orça
  roca
  </code></pre>
  
  <p>How can I fix it?</p>