title: sed: Replace FIRST occurence of space with newline
body: <p>I am trying to replace the <em>first</em> occurrence of a space in each line with a newline. </p>
  
  <p>For instance</p>
  
  <pre><code>123 there is a monkey
  567 there is also a tiger
  </code></pre>
  
  <p>would become</p>
  
  <pre><code>123
  there is a monkey
  567
  there is also a tiger
  </code></pre>
  
  <p>I have tried doing this with the command:</p>
  
  <pre><code>sed -e 's/^\s\+/\n/g' output.txt &gt; new.txt
  </code></pre>
  
  <p>with no luck. I am also open to any other programs in linux that would allow me to do this such as awk, perl, or bash.</p>