The psacct package contains several utilities for monitoring process
activities, including ac, lastcomm, accton and sa. The ac command
displays statistics about how long users have been logged on. The
lastcomm command displays information about previous executed commands.
The accton command turns process accounting on or off. The sa command
summarizes information about previously executed commmands.
Install the psacct package if you'd like to use its utilities for
monitoring process activities on your system.