A word designator indicates which word or words of a given command line are
to be included in a history reference. A ‘:’ usually
separates the event specification from the word designator.
It may be omitted only if the word designator begins with a
‘^’, ‘$’, ‘*’, ‘-’ or ‘%’.
Word designators include:
0The first input word (command).
The nth argument.
^The first argument. That is, 1.
$The last argument.
%The word matched by (the most recent) ?str search.
-yA range of words; x defaults to 0.
*All the arguments, or a null value if there are none.
*Abbreviates ‘x-$’.
-Like ‘x*’ but omitting word $.
Note that a ‘%’ word designator works only when used in one of
‘!%’, ‘!:%’ or ‘!?str?:%’, and only when used after a
!? expansion (possibly in an earlier command). Anything else results
in an error, although the error may not be the most obvious one.