The shell has auto complete as well and most of the commonly used cmdlets have aliases for shell usage if you don't want to rely on auto complete. You can also create aliases if you so desire.

Edit: The side benefit of the verbosity is the discoverability of less used commands. Is it groupadd or addgroup? No question in Powershell, it would be Add-Group because of the Verb-Noun standard. Bash has all sorts of inconsistencies that require look-up if you don't use those commands often.

I think Powershell made a big mistake going with verb first. I know I want to do something with group but when I type group there is no auto complete. Now I type “add” and I get dozens or hundreds of suggestions which makes auto complete almost useless. They should have gone with target object first so when I type in group I get all the relevant auto complete suggestions.

I'd suggest the following.

  get-command add*group*

Or for brevity

  gcm add*group*

For reference, the Bash version is this:

  compgen -c | grep group

Edit:

Let's get crazier. You want custom tab completion to focus on the command's noun plus Bash style completion.

  $Function:OriginalTabCompletion = $Function:TabExpansion

  function TabExpansion($line,  $lastWord) {
      if ($line -match ('^!(.*)') {
          $lastWord = $lastWord.trimstart('!')
          Get-command -noun *$lastWord*
      } elseif {
          OriginalTabExpansion  $line $lastWord
      }
  }
  Set-psreadline -chord tab -function MenuComplete

  !group<TAB>

Oh man. Somebody who really knows PowerShell. That's really rare :-)