Shell Programming and Scripting

#!/bin/bash

RUN_FROM_DIR="/etc/location"

. ${RUN_FROM_DIR}/sync.conf
(
flock -x -w 5 200 || exit 1
#---------------------------------------------------------------
echo "Hi, I'm sleeping for 1 minute..."
sleep 60
echo "all Done."
#---------------------------------------------------------------
) 200>/var/lock/.myscript.exclusivelock
#end

#!/bin/bash

RUN_FROM_DIR="/etc/location"

. ${RUN_FROM_DIR}/sync.conf
{
flock -x -w 5 200 || {
  logger "locked"
  exit 1
}
#---------------------------------------------------------------
echo "Hi, I'm sleeping for 1 minute..."
sleep 60
echo "all Done."
#---------------------------------------------------------------
} 200>/var/lock/.myscript.exclusivelock
#end

#!/bin/bash
#
#	Vars
#
	PID=$$
	LOCK=/tmp/${0##/*}.lock
	LOCK_USED=false
#
# 	Reset lockfile upon exit
#
	trap "echo > $LOCK" ERR ABRT KILL
#
#	Preps
#
	if [ ! -f $LOCK ]
	then	echo "No lockfile found..."
		touch $LOCK
	elif [ -s $LOCK ]
	then	echo "Lockfile found, and empty"
	else 	echo "Lockfile found, and/or non-empty = busy"
		LOCK_USED=true
	fi
#
#	Action
#
	if $LOCK_USED
	then	echo "Aborting, script is already running at PID: $(<$LOCK_FILE)"
		exit 1
	else	# Save the current PID in the file
		echo $PID > $LOCK
	fi
#
#	Actual script
#
	echo "Do your stuff..."