operating on dired marked files

[largo-linux]

I would like to mark a number of files in dired and then use those
files as arguments to a command.

but when i try this in dired, i.e. i mark three files then hit ! and
then perhaps a perl script.  it seems only to output the results of the
third file.  is there a way to do this so that it executes

script.pl file1.txt file2.txt file3.txt

???

thanks.