Backup of postgres

Hi all,

I have following script to backup database:
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#!/bin/sh

PSQL=/usr/local/pgsql/bin/psql
DUMP=/usr/local/pgsql/bin/pg_dump
PREFIX=`date +%j`
BACKUP_DIR=/usr/local/pgsql/data/base/.BACKUP

Databases=`$PSQL -tq -d template1 -c "select datname from pg_database"`
renice 20 $$

echo Backup started ...
for db in `echo $Databases`
do

  echo "time: `date +%H%M%S` - Backup of $db in progress ..."
  $DUMP -D $db > /$BACKUP_DIR/$PREFIX.$db
  echo "time: `date +%H%M%S` - Backup of $db finnished ..."
done
echo Backup finnished ...
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Crontab runs it every night (4:00am - nobody is working on the machine).
But every run I have following message:

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From: Cron Daemon <root@shire.st3.makro.com.pl>
To: postgres@shire.st3.makro.com.pl
Subject: Cron <postgres@shire> /usr/local/pgsql/store3/Backup.sh

3986: old priority 0, new priority 20
Backup started ...
time: 040001 - Backup of template1 in progress ...
time: 040004 - Backup of template1 finnished ...
time: 040004 - Backup of mzo in progress ...
time: 040010 - Backup of mzo finnished ...
time: 040010 - Backup of store3 in progress ...
/usr/local/pgsql/store3/Backup.sh: line 19:  4002 Segmentation fault      $DUMP -D $db >/$BACKUP_DIR/$PREFIX.$db
time: 042021 - Backup of store3 finnished ...
Backup finnished ...
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What's wrong with this script ?
It is running on Linux 2.0.33, Pentium 200, 64MB.
Please help - we save in postgres huge number of data.

przemol