The top program provides a dynamic real-time view of a running system. It can display system summary information as well as a list of tasks currently being managed by the Linux kernel. The types of system summary information shown and the types, order and size of information displayed for tasks are all user configurable and that configuration can be made persistent across restarts.
The program provides a limited interactive interface for process manipulation as well as a much more extensive interface for personal configuration -- encompassing every aspect of its operation. And while top is referred to throughout this document, you are free to name the program anything you wish. That new name, possibly an alias, will then be reflected on top's display and used when reading and writing a configuration file.
top -hv | -abcHimMsS -d delay -n iterations -p pid [, pid ...]
[root@server1 ~]# top top - 14:53:28 up 6 days, 14:08, 1 user, load average: 0.06, 0.05, 0.01 Tasks: 131 total, 1 running, 130 sleeping, 0 stopped, 0 zombie Cpu(s): 0.3%us, 0.3%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 1021964k total, 965568k used, 56396k free, 171436k buffers Swap: 2064376k total, 0k used, 2064376k free, 561180k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1632 mysql 20 0 132m 12m 2016 S 0.3 1.2 4:55.92 mysqld 1 root 20 0 2900 1300 1072 S 0.0 0.1 0:04.18 init 2 root 20 0 0 0 0 S 0.0 0.0 0:00.10 kthreadd 3 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0 4 root 20 0 0 0 0 S 0.0 0.0 0:00.21 ksoftirqd/0 5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0 6 root RT 0 0 0 0 S 0.0 0.0 0:01.90 watchdog/0 7 root 20 0 0 0 0 S 0.0 0.0 0:34.80 events/0 8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cgroup 9 root 20 0 0 0 0 S 0.0 0.0 0:00.00 khelper 10 root 20 0 0 0 0 S 0.0 0.0 0:00.00 netns 11 root 20 0 0 0 0 S 0.0 0.0 0:00.00 async/mgr 12 root 20 0 0 0 0 S 0.0 0.0 0:00.00 pm 13 root 20 0 0 0 0 S 0.0 0.0 0:01.66 sync_supers 14 root 20 0 0 0 0 S 0.0 0.0 0:01.53 bdi-default 15 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kintegrityd/0 16 root 20 0 0 0 0 S 0.0 0.0 0:09.35 kblockd/0 17 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kacpid 18 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kacpi_notify 19 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kacpi_hotplug 20 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata/0 21 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata_aux 22 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksuspend_usbd ........