## for -print (or ls or other newline-delimited names)
find ... -print | perl -pi.bak -e 'BEGIN { chomp(@ARGV = <STDIN>) } s/foo/bar/g'
## for -print0 (safer when names may contain newline)
find ... -print0 | perl -pi.bak -e 'BEGIN { local $/ = "\0"; chomp(@ARGV = <STDIN>) } s/foo/bar/g'