For those who care. Here is how you determine the disk space used for each
postgresql db.
#!/bin/bash
# scan the list of databases and provide the disk space used in human
readable form
dbs=`psql template1 -tc "select datname from pg_database"|sed s/" "/""/g`
for i in $dbs
do
oid=`psql template1 -tc "select oid from pg_database where datname =
'$i'"|sed s/" "/""/g`
echo "$i = "`du -sh "/var/lib/postgres/data/base/$oid"|awk '{print $1}'`
done
Tony