title: How echo a datetime in "YYYY-MM-DD" format in linux and powershell with a same command?
body: <p>I do have a php 'composer' command which generates a .zip package for deploy. </p>
  
  <p>this package should have the datetime as sufix, for instance <code>release-2018-09-12</code> or <code>release-2018091</code>.</p>
  
  <p>However some of our programmers and freelancers use both windows and Linux.</p>
  
  <p>The <code>date +%Y-%m-%d</code> only works on Linux. but not on windows.</p>
  
  <p>How can I write a command that works both in Linux or windows (powershell)? or a workaround to it?</p>