Red Hat Enterprise Linux 5 Administration Unleashed

Reporting System Processes 411TABLE 20.3top HeaderPIDUSERPRNIVIRTRESSHRS%CPU%MEMTIME+COMMANDExplanation of top HeadersExplanationProcess IDOwner of processProcess priorityNice valueVirtual memory used by processNon-swapped physical memory used by the processShared memory used by the processStatus of processPercentage of CPU usagePercentage of physical memory usageTotal CPU time used by processCommand used to start the processtop is also interactive. For example, pressing Shift+M sorts the output by memory usage.Other sorting options are listed in Table 20.4.TABLE 20.4top CommandShift+MShift+PShift+NShift+TkuspacebarhqInteractive top CommandsExplanationSort by memory usageSort by CPU usageSort by PIDSort by TIME+Kill a specific process by PIDSort by specific userImmediately refresh the outputShow helpQuit topTo view the same information graphically, select Administration, System Monitor fromthe Systems menu on the top panel of the desktop. As shown in Figure 20.3, theProcesses tab shows the information from the top command in an easier to read format.Click on a column name to sort the information by the data in the column.All of these tools can be used to determine if one or a small group of processes is consumingthe majority of the system resources. This is especially useful on a server shared bymany.20TIPWant to quickly find out who owns the process taking up the most resources? Try the wcommand. It lists all users currently logged on and all their processes.