ls testfile | perl -lpi -e 's/e/*/'

##</code><code>##

ls testfile | xargs perl -lpi -e 's/e/*/'

##</code><code>##

find ... -print | perl -pi.bak -e 'BEGIN { chomp(@ARGV = <STDIN>) } s/foo/bar/g'

##</code><code>##

LINE: while (<>) {
  ...
}

##</code><code>##

LINE: while (@ARGV) {
  ...
}