Como eliminar todas as conexões do Postgres

#!/usr/bin/env bash
# kill all connections to the postgres server
if [ -n "$1" ] ; then
where="where pg_stat_activity.datname = '$1'"
echo
"killing all connections to database '$1'"
else
where="where pg_stat_activity.datname in (select datname from pg_database where datname != 'postgres')"
echo
"killing all connections to database"
fi

cat
<<-EOF | psql -U mhenrixon -d postgres
SELECT pg_terminate_backend
(pg_stat_activity.pid)
FROM pg_stat_activity

$
{where}
EOF