title: I am trying to replace a string in a file via shell script where a part of the string is unknown
body: <p>I have tried a few ways with sed as below without success:</p>
  
  <pre><code>sudo sed -i 's/(device.value=).*( )/\1 90 \2/g' /boot/cmdline.txt
  sudo sed -i 's/device.value=.* /device.value=90/g' /boot/cmdline.txt
  </code></pre>
  
  <p>I do not know the value behind "=" which can have up to 2 digits.
  Before and after the string there is a space, and the string always starts with "device.value=" </p>
  
  <p>PS: The file is a one liner with many values seperated through a space.</p>
  
  <p>I would appreciate any help. Thx</p>