A list of those programs you only need once in a blue moon but can never remember the name of.

• lsof - list all file handles. Can be useful when a filesystem won't unmount.
• modinfo - describe module and arguments that can be provided
• top - list the most active processes based on CPU and memory.
• atop - lists the most active processes based on CPU, memory, disk and network usage
• iotop - lists io usage of programs.
• sysv-rc-conf - manage run level of programs in init
• gdmap or baobab - visualise disk usage
• gpicview - lightweight GTK image viewer

• iftop - lists network usage by ip address
• iptraf -
• nethogs - per process network usage