Sams Teach Yourself Shell Programming in 24 Hours, Second Edition

Hour 19

1:	The following is the main body of the “live” script presented earlier in this chapter. Change the script such that SIGQUIT causes it to exit after the wait command returns. # main() trap CleanUp 2 3 15 trap Init 1 PROG=$1 Init while : ; do wait $! $PROG & done
A1:	Here is a possible implementation: trap CleanUp 2 15 trap Init 1 trap "quit=true" 3 PROG="$1" Init while : ; do wait $! if [ "$quit" = true ] ; then exit 0 ; fi $PROG & done
2:	Add a signal handler to the timer script to handle SIGINT.
A2:	Here is a possible implementation: #! /bin/sh AlarmHandler() { echo "Got SIGALARM, cmd took too long." KillSubProcs exit 14 } IntHandler() { echo "Got SIGINT, user interrupt." KillSubProcs exit 2 } KillSubProcs() { kill ${CHPROCIDS:-$!} ...