title: What is the difference between `sed -i -e` and `sed -ie`?
body: <p>What is the difference between <code>sed -i -e</code> and <code>sed -ie</code> ?
  It's not very clear from help
  <code>sed --help</code></p>
  
  <pre><code>  -e script, --expression=script
                   add the script to the commands to be executed
  </code></pre>
  
  <p>In second case it creates some backup file?</p>
  
  <p>In general Unix utils do not permit to combine flags?</p>
  
  <p>Just an example to show what is happening:</p>
  
  <pre><code>echo "bla" &gt; 1.txt
  cat 1.txt
  bla
  sed -i -e 's:bla:blakva:g' 1.txt
  cat 1.txt
  blakva
  sed -ie 's:bla:blakva:g' 1.txt
  cat 1.txt
  blakvakva
  *Note: also 1.txte is created, containing
  cat 1.txte
  blakva
  </code></pre>
  
  <p>Also not still sure what is <code>-e</code> doing in my example, because <code>sed -i 's:bla:blakva:g' 1.txt</code> works too.</p>