16 "top"-Like Linux Apps / Commands

htop - Undoubtedly the most famous of the top-like tools. It implements some extra options to the "top" command, like colors, ability to scroll horizontally and vertically, and a better interaction with the processes listed.

itop - Monitors the system breaks.

atop - Monitor for system resources. Displays swap, network, disk, cpu, activity, among other processes.

sntop - Pings a list of hosts and indicates whether they are active or inactive. Must be configured in /etc/sntoprc.

mtop, mytop - tools that monitor the performance and queries of a mysql database.

apachetop - Displays information about Apache, such as requests per second, bytes per second and the most popular URLs.

ptop - Similar to mtop, but specific to postgres.

dnstop - Displays information about the network's DNS traffic.

virt-top - Displays details of virtualised systems: cpu, memory, uptime. You can monitor any system based on libvirt virtualisation such as Xen and KVM.

iptstate - Displays information about connections which pass through your firewall / gateway. It is basically a netstat that monitors the connections handled by iptables. Depends on module CONNTRACK.

ntop, jnettop - Displays information on the network bandwidth, each with its peculiarity - From the same class as previously mentioned iftop.

nethogs - network information, but instead of displaying the traffic by protocol, nethogs shows the bandwidth usage by process. Very interesting.

You can find all of these in Ubuntu 9.04, by searching using Synaptic Package Manager.