Brent -
One way to limit the duration of a command is to run it in a
subprocess (i.e. put the shell command in parentheses) and have the
parent kill it. Here's an example:
#!/bin/bash
# try to send a string to the synthesizer via four different serial
#ports
for x in 0 1 2 3; do
(DTK_PORT=/dev/ttyS$x
echo "trying $DTK_PORT"
stty sane 9600 raw -echo crtscts <$DTK_PORT &&\
stty -echo <$DTK_PORT &&\
stty ixon ixoff <$DTK_PORT &&\
echo "this is /dev/t t y s $x" $'\r' >$DTK_PORT )&
# if one of the above commands hangs, kill the process
sleep 2; kill $! >/dev/null 2>&1
done
- Jim Van Zandt