LINUX is a multi-user system, once connected to the network, it can provide services for multiple logged-in users at the same time. The system administrator can know which users are in the system at any time and what operations the users are doing.
View the user's operation
If the system administrator wants to know the user's behavior at a certain time, he only needs to enter the command w, and enter the following command in the SHELL terminal:
tux@tux-desktop:~$ w
21:13:14 up 7:08, 2 users, load average: 0.22, 0.32, 0.20
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
tux tty7 :0 14:05 ? 37:55 0.33s x-session-manag
tux pts/1 :0.0 21:13 0.00s 0.13s 0.00s wThe first line displays the summary information of the system, and the fields represent the current time of the system, the running time of the system, the total number of logged-in users, and the average load information of the system . The meaning of the displayed data for several of the above forces is:
21:13:14 means that the time to execute W is at 9:13 pm.
7:08 means that the system runs for 7 hours and 8 minutes.
2 users means that the total number of logged-in users in the current system is 2.
The load average and the following numbers indicate the load level of the system in the past 1, 5, and 10 minutes. The smaller the value, the lighter the system load.
Starting from the second row, a table is formed, with 8 columns in total, which respectively display what each user is doing and the system information occupied by the user.
USER: Display the login user account name. If the user logs in repeatedly, the account will also appear repeatedly.
TTY: The terminal used by the user to log in.
FROM: Displays where the user logs into the system.
LOGIN@: It means LOGIN AT, which means the time of logging in and entering the system.
IDLE: The user's idle time, since the user's last task ends, the meeting time.
JCPU: It is distinguished by a terminal code, which indicates the CPU time consumed by all process tasks related to the terminal within a period of time.
PCPU: Refers to the CPU time spent after tasks in the WHAT domain are executed.
WHAT: Indicates the currently executing task
view kernel
# cat /proc/version
Linux version 3.10.0-123.9.3.el7.x86_64 ([email protected]) (gcc version 4.8.2 20140120 (Red Hat 4.8.2-16) (GCC) ) #1 SMP Thu Nov 6 15:06:03 UTC 2014
View releases
# lsb_release -a LSB Version: :core-4.1-amd64:core-4.1-noarch Distributor ID: CentOS Description: CentOS Linux release 7.0.1406 (Core) Release: 7.0.1406 Codename: Core
View CPU information
[root@iZ28cb8geghZ proc]# cat /proc/cpuinfo processor : 0 #Logical processor ID (number of logical cpu cores) vendor_id : GenuineIntel #CPU manufacturer cpu family : 6 #CPU product series code model : 45 #CPU belongs to the code name of the generation of this series model name : Intel(R) Xeon(R) CPU E5-2630 0 @ 2.30GHz #CPU belongs to the name and number, nominal frequency stepping : 7 #CPU updated version microcode : 0x70d # cpu MHz : 2300.020 #The actual frequency of the CPU cache size : 15360 KB #CPU L2 cache size physical id : 0 #The label of a single CPU siblings : 1 #"Number of logical processors" in processors in the same physical package, equivalent to the number of threads core id : 0 #id of each core cpu cores : 1 # "Number of cores" in processors in the same physical package apicid : 0 #Used to distinguish the number of different logical cores, the number of each logical core in the system must be different, this number is not necessarily continuous initial apicid : 0 # fpu : yes #whether it has a floating point unit fpu_exception : yes #whether floating-point calculation exceptions are supported cpuid level: 13 #Before executing the cpuid instruction, the value in the eax register will return different contents according to different values. wp : yes #Indicates whether the current CPU supports write protection for user space in kernel mode (Write Protection) flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl pni ssse3 cx16 sse4_1 sse4_2 popcnt aes hypervisor lahf_lm bogomips : 4600.04 #Roughly estimated CPU speed when the system kernel is started (Million Instructions Per Second) clflush size : 64 #The size unit of each flush cache cache_alignment : 64 #Cache address alignment unit address sizes : 46 bits physical, 48 bits virtual #Accessible address space bits power management: #Support for energy management, with the following optional support functions