$ $(echo {a..z})
`CTRL` \+ `ALT` \+ `e`
$ a b c d e f g h i j k l m n o p q r s t u v w x y z
Note that it will expand all the expansions on the command line. No matter where the cursor is placed.
With this command (and `a=this; b=that`):
$ echo "$a"; $(echo {a..m}); echo "$b"
This will be expanded:
$ echo this; a b c d e f g h i j k l m ; echo that
From `man bash`:
> shell-expand-line (M-C-e)
> Expand the line as the shell does. This performs alias and history expansion as well as all of the shell word expansions. See HISTORY EXPANSION below for a description of history expansion.