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+#!/bin/bash
+#
+# The Bash shell script executes a command with a time-out.
+# Upon time-out expiration SIGTERM (15) is sent to the process. If the signal
+# is blocked, then the subsequent SIGKILL (9) terminates it.
+#
+# Based on the Bash documentation example.
+
+# Hello Chet,
+# please find attached a "little easier" :-) to comprehend
+# time-out example. If you find it suitable, feel free to include
+# anywhere: the very same logic as in the original examples/scripts, a
+# little more transparent implementation to my taste.
+#
+# Dmitry V Golovashkin <Dmitry.Golovashkin@sas.com>
+
+scriptName="${0##*/}"
+
+declare -i DEFAULT_TIMEOUT=9
+declare -i DEFAULT_INTERVAL=1
+declare -i DEFAULT_DELAY=1
+
+# Timeout.
+declare -i timeout=DEFAULT_TIMEOUT
+# Interval between checks if the process is still alive.
+declare -i interval=DEFAULT_INTERVAL
+# Delay between posting the SIGTERM signal and destroying the process by SIGKILL.
+declare -i delay=DEFAULT_DELAY
+
+function printUsage() {
+ cat <<EOF
+
+Synopsis
+ $scriptName [-t timeout] [-i interval] [-d delay] command
+ Execute a command with a time-out.
+ Upon time-out expiration SIGTERM (15) is sent to the process. If SIGTERM
+ signal is blocked, then the subsequent SIGKILL (9) terminates it.
+
+ -t timeout
+ Number of seconds to wait for command completion.
+ Default value: $DEFAULT_TIMEOUT seconds.
+
+ -i interval
+ Interval between checks if the process is still alive.
+ Positive integer, default value: $DEFAULT_INTERVAL seconds.
+
+ -d delay
+ Delay between posting the SIGTERM signal and destroying the
+ process by SIGKILL. Default value: $DEFAULT_DELAY seconds.
+
+As of today, Bash does not support floating point arithmetic (sleep does),
+therefore all delay/time values must be integers.
+EOF
+}
+
+# Options.
+while getopts ":t:i:d:" option; do
+ case "$option" in
+ t) timeout=$OPTARG ;;
+ i) interval=$OPTARG ;;
+ d) delay=$OPTARG ;;
+ *) printUsage; exit 1 ;;
+ esac
+done
+shift $((OPTIND - 1))
+
+# $# should be at least 1 (the command to execute), however it may be strictly
+# greater than 1 if the command itself has options.
+if (($# == 0 || interval <= 0)); then
+ printUsage
+ exit 1
+fi
+
+# kill -0 pid Exit code indicates if a signal may be sent to $pid process.
+(
+ ((t = timeout))
+
+ while ((t > 0)); do
+ sleep $interval
+ kill -0 $$ || exit 0
+ ((t -= interval))
+ done
+
+ # Be nice, post SIGTERM first.
+ # The 'exit 0' below will be executed if any preceeding command fails.
+ kill -s SIGTERM $$ && kill -0 $$ || exit 0
+ sleep $delay
+ kill -s SIGKILL $$
+) 2> /dev/null &
+
+exec "$@"