Changes in version 1.22.1:

Ed now departs from POSIX and ignores SIGPIPE to prevent commands like
'w !:' or ',!:' from terminating ed. A broken pipe is now detected as any
other write error. (Reported by Sergei Trofimovich).

Changes in version 1.22:

The shell escape command (!) now accepts line addresses to filter the
addressed lines through a shell command. (ex(1) style filter).
(Suggested by Shawn Wagner, Andrew L. Moore, and John Cowan).
