document parse env

readme.markdown

@@ -60,10 +60,13 @@ var parse = require('shell-quote').parse;
 Return a quoted string for the array `args` suitable for using in shell
 commands.
 
-## parse(cmd)
+## parse(cmd, env={})
 
 Return an array of arguments from the quoted string `cmd`.
 
+Interpolate embedded bash-style `$VARNAME` and `${VARNAME}` variables with
+the `env` object which like bash will replace undefined variables with `""`.
+
 # install
 
 With [npm](http://npmjs.org) do: