Fing is a command line tool for network and service discovery. It provides you a complete view of any network in a very short time. Its smart discovery automatically detects the network type and uses the best technique to scan it. The best results are achieved on Ethernet networks (including Wireless ones), where Fing is able to detect all network hosts, firewalled ones included. The service discovery feature quickly detects active TCP services on a target host or network. Fing is based on Look@LAN.
downtimed is a program that monitors operating system downtime, uptime, shutdowns, and crashes and records such events. At OS startup it logs information about previous downtime. It then periodically updates a time stamp file on the disk, which is used to determine the approximate time when the system was last up and running. During a graceful system shutdown, it records a time stamp in another file. The downtimes(1) command line tool can be used to inspect records of past downtime.