как забиндить отправку SIGUSR по аналогии с SIGINT/Ctrl+C ?

#!/bin/bash

# based on
# keypress.sh: Detect a user keypress ("hot keys").

echo

echo "starting $1.."
echo

$1 &

CHILDPID=$!
echo "
process started with $CHILDPID pid..
let's check it..
"
ps auxww | grep -v grep | grep $CHILDPID
echo

old_tty_settings=$(stty -g)   # Save old settings (why?).
stty -icanon
while true
  do
    Keypress=$(head -c1)
    echo
    echo "$Keypress was pressed"
    if [ "$Keypress" == "u" ]
      then
        kill -USR1 $CHILDPID
    fi
    if [ "$Keypress" == "c" ]
      then
        kill $CHILDPID
#       sleep 1
#        kill -9 $CHILDPID
        break
    fi
  done

stty "$old_tty_settings"      # Restore old settings.

# Thanks, Stephane Chazelas.

exit 0

#!/bin/bash

# based on
# keypress.sh: Detect a user keypress ("hot keys").

echo

echo "starting $1.."
echo

$1 &

CHILDPID=$!
echo "
process started with $CHILDPID pid..
let's check it..
"
ps auxww | grep -v grep | grep $CHILDPID
echo

old_tty_settings=$(stty -g)   # Save old settings (why?).
stty -icanon

trap 'kill $CHILDPID ; stty "$old_tty_settings" ; exit 0' 2

while true
  do
    Keypress=$(head -c1)
    echo
    echo "$Keypress was pressed"
    if [ "$Keypress" == "u" ]
      then
        kill -USR1 $CHILDPID
    fi
  done

# Thanks, Stephane Chazelas.

exit 0