#!/bin/bash # spawn.sh PIDS=$(pidof sh $0) # Process IDs of the various instances of this script. P_array=( $PIDS ) # Put them in an array (why?). echo $PIDS # Show process IDs of parent and child processes. let "instances = ${#P_array[*]} - 1" # Count elements, less 1. # Why subtract 1? echo "$instances instance(s) of this script running." echo "[Hit Ctl-C to exit.]"; echo sleep 1 # Wait. sh $0 # Play it again, Sam. exit 0 # Not necessary; script will never get to here. # Why not? # After exiting with a Ctl-C, #+ do all the spawned instances of the script die? # If so, why? # Note: # ---- # Be careful not to run this script too long. # It will eventually eat up too many system resources. # Is having a script spawn multiple instances of itself #+ an advisable scripting technique. # Why or why not?
