Monitoring System Activity

One of the advantages of a multiuser, multiprocess, operating system like Linux

is the ability to run many programs simultaneously, as well as handling various

users, and keep track of both at the same time. Under these circumstances it is

necessary to be able to monitor the system for things like runaway programs,

and memory hogs, so that these problems can be dealt with effectively.

Process Status

Executing the command ps returns a list of processes being run by the user

account that invokes the command. This list includes the process id, the

command that started the process, and the terminal type and number.

Any process in the list may be terminated using the kill command with the

associated process id obtained from the list generated by ps.

To see a list of all processes use the ps  a command. Unless done by the root

account, only the listed processes which the user started may be killed by

that user. The root account can kill any process on the system with kill  9

.

While the ps command includes a field for the status of the process, the

only process in a R(un) status is the process ps itself. All other processes are

marked S(uspended). Another tool is required to get a real time picture of

what these processes are doing.

top CPU Processes

The system utility top provides a continuous, real time look at the system's

consumption of memory and CPU resources. It lists the most consumptive

process first, so finding that process that is gobbling machine resources is

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