How to find which version of ESXi you’re running from the command line?

  If you’re remotely logging in to a server to apply the latest patch but can’t remember whether you’re running 4, 4.1, 5.0 or 5.1 – and it can certainly happen when you’re managing quite a few of them remotely – there is a handy command to see which version and build number you’re actually using. After you’ve SSH’d in, run:  
vmware -v
  This will display output along the lines of the following:  
VMware ESXi 5.0.0 build-469512
  You can also use:  
vmware -l
  which doesn’t display the build number:  
VMware ESXi 5.0.0 GA
  Straightforward but very handy if you haven’t got the proper notes with you.