standard input to commands in a shell script

[Shiping Zhang]

In response to my post on the subject, many people either posted
on this group or mailed me directly. Their messages are very helpful
to me. I'm very grateful to their help. The posts have covered all
I got from email, so I'm not going to post a summary here, assuming
all of you who are interested in this subject read all the posts.
If anyone feels missing something, please mail to me, I'll mail
back whatever I know. Thanks again.

-ping