Nagios is a host, service, and network monitoring system that will watch your network and alert you to problems before your clients or end-users do. The system runs checks on hosts and services that you specify using plugins that return status information to Nagios. When problems are encountered, the system will send notifications to system administrators so that they can take action on the problem. The JumpBox for Nagios gives you a head start to using the system. It eliminates the complexity involved in getting the application installed, and allows you to focus on the configuration for your specific environment. Since Nagios is based on plugins, depending on what you want to do this will vary in complexity.
digup is a console tool to update md5sum or shasum digest files. It will read existing digest files, check the current directory for new, updated, modified, renamed, or deleted files, and query the user with a summary of changes. After reviewing the updates, they can be written back to the digest file. This makes digup very useful to update and verify incremental archives like chronological data storages, which are commonly stored and backed up on hard disks. Using a full file digest scan, even slowly creeping bad blocks on old hard disks can be detected. By using a crontab entry, this check can be performed unattended and routinely.