1: #!/bin/bash
   2: # Try this under bash, ksh and sh
   3: 
   4: trap huphandler  HUP
   5: trap ''          QUIT
   6: trap exithandler TERM INT
   7: 
   8: huphandler()
   9: {
  10:    echo 'Received SIGHUP'
  11:    echo "continuing"
  12: }
  13: 
  14: exithandler()
  15: {
  16:    echo 'Received SIGTERM or SIGINT'
  17:    exit 1
  18: }
  19: ## Execution starts here - infinite loop until interrupted
  20: # Use ":" or "true" for infinite loop
  21: # SECONDS is built-in to bash and ksh.  It is number of seconds since script started
  22: : is like a comment, but it is evaluated for side effects and evaluates to true
  23: seconds=0
  24: while : ; do
  25: # while true; do
  26:    sleep 5
  27:    seconds=$((seconds + 5))
  28:    echo -n "$SECONDS $seconds - "
  29: done