This first pipeline works fine (printing "c"):
echo "a" | sed 's/a/b/' | sed 's/b/c/'
This one does not do what I expect (nothing gets printed when I feed an "a" into my fifo ):
mkfifo fifo; cat fifo | sed 's/a/b/' | sed 's/b/c/'
However, if I remove the second "sed" command from the latter pipeline, I do get a "b" printed. I think my understanding of pipes and redirects must be too simplistic. Can someone explain to me how to fix the 2nd case so that I can run two successive commands on the contents of the fifo?
(note this isn't a problem specific to fifo, the same behavior occurs with netcat too. I posted a similar question about netcat but got no answers)