sed, bash script

[Ric Otte <ric@otte.ucsc.edu>]

Hi,
I would like to run all of the files in some directories through sed, in
order to edit the files.  I can do it for individual files by typing:
  cat filename|sed command>filename
But that requires me to run that command for each file.  I was wondering if
anyone could 1) give me a reference to a simple bash tutorial that will
explain how to set up a script to do things like this, and 2) tell me how to
do it.  I was thinking I could set up an alias FOO and type 'FOO *' , but I
haven't been able to get that to work--I don't know how to refer to the
filename in the alias.

Thanks,

Ric