using perl on the command line, like sed or awk

From: gorda (smith4894_at_excite.com)
Date: 10/20/03 

Date: 20 Oct 2003 14:40:54 -0700

Hello,

Using sed or awk, I can quickly parse and perform operations on the
command line itself as in:

cat file | sed 's/cat/dog'
cat file | awk ' /cat/ {print "found the cat"} '

How can i do something like the above in perl on the command line
without having to write a script in a seperate file?

Thanks
-s