写一段定时备份PG数据库的脚本

以下是一段定时备份PG数据库的脚本：

#!/bin/bash

# Set the POSTGRES password
export PGPASSWORD="password"

# Set the backup directory
BACKUP_DIR="/var/backups/postgresql"

# Set the date format for the backup file name
DATE=`date +%Y-%m-%d_%H-%M-%S`

# Set the name of the backup file
BACKUP_FILE="pg_backup_$DATE.sql.gz"

# Set the name of the database to backup
DATABASE="mydatabase"

# Run the backup command and compress the output
pg_dump -U postgres $DATABASE | gzip > "$BACKUP_DIR/$BACKUP_FILE"

# Delete any backups older than 7 days
find $BACKUP_DIR -mtime +7 -type f -delete

# Echo a message to confirm the backup was successful
echo "Backup successful: $BACKUP_DIR/$BACKUP_FILE"