Bash Read -t but in milliseconds?

Question

Hi in my code I have while loop and at the beginning of that while loop, I use the read function to make kill function. So every time the program goes through the loop it will first check if you pressed the kill button.

Problem is, is that the read command timeout cannot be shorter than 1 second. This makes the program annoyingly slow.

Is there a way to time out the read command in milliseconds? or should I work with something else to kill the program?

while(true)

do
 read -n1 -t 0.01 killer
 if [ "$killer" == "k" ]
 then
   echo "ill!!!"
   pkill -9 -e -f gnome-terminal- # a ros node that's running in the background
   pkill -9 -e -f Test_PI.sh # the name of the bash
 fi

 echo "working"
 clear
done

Answer 1

You are incorrect, read can handle fractional timeouts.

$ time read -t 0.4
real    0m0.400s
user    0m0.000s
sys     0m0.000s

So I would alter your script into

while true; do
  if read -n1 -t 0.01 key; then
     if [[ "$key" == "k" ]]; then
        ...
     fi
  fi
done

Or if you make use of the zero timeouts, you can do

while true; do
  if read -t 0 && read -n1 key; then
     if [[ "$key" == "k" ]]; then
        ...
     fi
  fi
done

---

-t timeout :: Cause read to time out and return failure if a complete line of input is not read within timeout seconds. timeout may be a decimal number with a fractional portion following the decimal point. This option is only effective if read is reading input from a terminal, pipe, or other special files; it has no effect when reading from regular files. If timeout is 0, read returns success if input is available on the specified file descriptor, failure otherwise. The exit status is greater than 128 if the timeout is exceeded.

_{Source: man bash, section read}