This could be a useful feature in some situations.

How about:

/filter -h#

-> Automatically stops filtering after the #th match.
-> Example: /filter -ffh3 infile.txt outfile.txt *


and also:

/filter -h
or
/stopfilter

-> Manually stop the calling /filter command. (Must be used in the -k alias)
-> Example: /filter -ffk infile.txt /outalias *
--> alias outalias { if (d isin $1-) filter -h

-genius_at_work