Keep an OSM Database up to date over a particular bounding box. There are probably lots of different versions of this around.

gistfile1.txt

#!/bin/bash
#This scripts updates the area and inserts the changes into the database

SLEEP_TIME=30s
BBOX="-6.5,49.5,2.1,59.0"  # United Kingdom
DBUSER=graham
DBNAME=osm_gb

WORKDIR_OSM=/home/osmdb
OSMOSIS_CHANGE_FILE=changes.osc.gz
OSMOSIS=/usr/local/bin/osmosis
OSM2PGSQL=/usr/bin/osm2pgsql

PID_FILE="/var/run/osmosis.pid"
SLEEP=/bin/sleep

#Update-Intervall is parameter 1
if [ "$1" != "" ]; then
  SLEEP_TIME=$1;
fi

if [ -e $PID_FILE ]; then
	echo "Is already running";
	exit 1
fi

echo $$ > $PID_FILE

echo "Change file is "$WORKDIR_OSM/$OSMOSIS_CHANGE_FILE

while [ 0 ]; do
	date
	time $OSMOSIS --read-replication-interval workingDirectory=$WORKDIR_OSM --simplify-change --write-xml-change $WORKDIR_OSM/$OSMOSIS_CHANGE_FILE
	time $OSM2PGSQL --append -S default.style --slim  --bbox $BBOX -U $DBUSER -d $DBNAME -C 8192 $WORKDIR_OSM/$OSMOSIS_CHANGE_FILE 
	echo "Sleeping for "$SLEEP_TIME
	$SLEEP $SLEEP_TIME
	echo "***********************************************"
done