Linux read form serial port - fork workaround

Question

I'm trying to send data via serial port and receive the response. Currently I'm looping the interface physically to emulate the device. first I do:

# stty -F /dev/ttyUSB0 -echo

if I try to read after write, it doesn't print anything:

# echo "foo" > /dev/ttyUSB0; cat /dev/ttyUSB0

I have to fork the read before write to get the response.

# cat /dev/ttyUSB0 &
[1] 7881

# echo -ne "foo\xA\0"
foo

Is there a work around?

Thank you!

Answer 1

Assuming that you've got the correct read and write privileges for /dev/ttyUSB0. You simply need to have the echo running on one terminal:

echo -ne 'foo\xA\0' >  /dev/ttyUSB0 

and the cat running on another terminal (use the -v option to make all characters readable):

cat -v /dev/ttyUSB0