http://man.freebsd.org/sed

also reading the ed man page will help as well for newbies.

--------------------------

IEEE Std 1003.1-2008 :

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ed...

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ex...

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/se...