[sisk]

zsh also supports the "alias anywhere" concept (their term is "global alias") by using the `-g` flag.

   alias -g ag='2>&1 | grep'
   some-command ag 'words' # equivalent to: some-command 2>&1 | grep 'words'

[alkh]

Yeah, it's very convenient. Here are a few of mine(tested on OS X):

  alias -g L="| less"
  alias -g T="| tee"
  alias -g C="| pbcopy"
  alias -g @all="> /dev/null 2>&1"
  if command -v rg > /dev/null; then
   alias -g G="| rg"
  else
   alias -g G="| grep"
  fi