Voici un petit script qui permet de tester une liaison série (avec et sans bouchon)

[bash]
#!/bin/bash

# connect.sh

# Usage:
# $ connect.sh <device> <port speed>
# Example: connect.sh /dev/ttyS0 9600

# Set up device
stty -F $1 $2 raw -echo

# Let cat read the device $1 in the background
cat $1 &

# Capture PID of background process so it’s possible to terminate it when done
bgPid=$?

# Send a string to the serial link
sleep 0.5
echo "Loop OK !!!" > $1
sleep 0.5

read -p "Press any keys…"
# Terminate background read process
kill $bgPid
[/bash]