Linux Dummies 9th

Chapter 18: Basic System Administration
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Checking Out the System Monitor
Although things usually go well on Linux systems, sometimes applications
can go awry. When that happens, it’s handy to be able to watch what’s going
on under the hood of the operating system.
The System Monitor tool provides information about how the system hardware
and software are working. It’s often included by Linux distributions to
provide a graphical peek at your system. Both Ubuntu and Fedora include
this feature by default.
To start the System Monitor tool, choose System➪Administration➪System
Monitor in Ubuntu, or choose Applications➪System Tools➪System Monitor
in Fedora. The System Monitor includes four tabs:
✓ System: Shows the hostname, hardware information, and system status
(available space on the hard drive).
✓ Processes: Shows information about programs currently running on the
system.
✓ Resources: Shows information about CPU and memory usage.
✓ File Systems: Shows information about what hard drives are mounted
on the system.
Of course, just having a bunch of information thrown at you doesn’t help at
all. You need to know what that information means so you can decide what to
do about it. The following sections help you understand how to interpret the
various pieces of information contained in the System Monitor.
Processes
Clicking the Processes tab provides an overview of the programs currently
running on the system, as shown in Figure 18-14.
Processes — the Linux term for programs running on the system — are
shown in a table format. The default view shows all the processes that are
currently being run by your user account. Alternatively, you can watch all
the processes — or just the ones that are actively working — by choosing
View from the menu bar and selecting which option you want to view. You
can base a sort of the table rows on any of the table columns; for example,
to see what processes are using the largest percent of CPU time, click the %
CPU column heading. The System Monitor sorts the rows automatically by
percentage of CPU usage.