Why is “echo foo | read a ; echo $a” not working as expected?

Question

I could replicate the problem with various shells under FreeBSD, GNU/Linux, and Solaris. It had me head-scratching for more than an hour, so I decided to post the question here

Answer 1

read expects input on a new line

while read a; do echo $a; done
foo
bar
^D

is more or less what you wanted