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groups
Prints the name of the group to which the specified user belongs.
overview
groups [OPTION]… [username]…
The main purpose
Prints the name of the group to which the specified user belongs.
Options
–help: Display help information and exit.
–version: Display version information and exit.
parameter
username (optional): It can be one or more. If not provided, it defaults to the current user.
return value
Returning 0 indicates success, returning a non-zero value indicates failure.
example
Display the groups to which the linux user belongs
[root@localhost ~]# groups linux
linux : linux adm dialout cdrom plugdev lpadmin admin sambashare
Note: This command is equivalent to id -Gn. Each user belongs to a group specified in /etc/passwd and other groups specified in /etc/group.
lpstat
Display status information of printers in CUPS
Additional information
The lpstat command is used to display the status information of printers in CUPS.
grammar
lpstat(options)
Options
-E: Encrypt when connecting to the printer;
-R: Display the level of the print task;
-U: Specify an optional user name;
-a: Display the printer that accepts the print task;
-c: Display the printer class;
-d: Display the default printer ;
-h: Specify optional server information;
-l: Display long format;
-p: Display the specified printer and whether the printer accepts print tasks;
-s: Display summary information;
-t: Display all status information.
mpstat
Display the status of each available CPU
Additional information
The mpstat command is mainly used in multi-CPU environments. It displays the status of each available CPU. This information is stored in the /proc/stat file. In a multi-CPUs system, it can not only view the average status information of all CPUs, but also view the information of a specific CPU.
grammar
mpstat(options)(parameters)
Options
-P: Specify the CPU number.
parameter
Interval: the interval between each report (seconds);
Count: the number of times the report is displayed.
Header meaning
%user: Indicates the percentage of CPU used by processing user processes.
%nice: Indicates the percentage of CPU when using the nice command to downgrade a process.
%system: Indicates the percentage of CPU used by the kernel process.
iowait: Indicates the percentage of CPU time spent waiting for I/O.
irq: Indicates the percentage of CPU used to handle system interrupts.
soft: Indicates the percentage of CPU used to handle software interrupts.
idle: The percentage of idle time of the CPU.
Example
When mpstat takes no parameters, the output is the average value since system startup.
mpstat
Linux 2.6.9-5.31AXsmp (builder.redflag-linux.com) 12/16/2005
09:38:46 AM CPU %user %nice %system %iowait %irq %soft %idle intr/s
09:38:48 AM all 23.28 0.00 1.75 0.50 0.00 0.00 74.47 1018.59
Statistics report for 2 processors was generated every 2 seconds:
The following command can generate statistical data reports for 2 processors every 2 seconds, generate a total of three interval information, and then give the average information of these three intervals. By default, the output is sorted by CPU number. The first line gives all active data since the system booted. Each subsequent line corresponds to the active state of a processor.
mpstat -P ALL 2 3
Linux 2.6.18-164.el5 (server.sys.com) 01/04/2010
09:34:20 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
09:34:22 PM all 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00 1001.49
09:34:22 PM 0 0.00 0.00 0.50 0.00 0.00 0.00 0.00 99.50 1001.00
09:34:22 PM 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00 0.00
Compare the results of mpstat with and without parameters:
Open a 2G file in the background
cat 1.img &
Then run the mpstat command in another terminal
mpstat
Linux 2.6.18-164.el5 (server.sys.com) 01/04/2010
10:17:31 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
10:17:31 PM all 0.07 0.02 0.25 0.21 0.01 0.04 0.00 99.40 1004.57
mpstat
Linux 2.6.18-164.el5 (server.sys.com) 01/04/2010
10:17:35 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
10:17:35 PM all 0.07 0.02 0.25 0.21 0.01 0.04 0.00 99.39 1004.73
mpstat 3 10
Linux 2.6.18-164.el5 (server.sys.com) 01/04/2010
10:17:55 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
10:17:58 PM all 13.12 0.00 20.93 0.00 1.83 9.80 0.00 54.32 2488.08
10:18:01 PM all 10.82 0.00 19.30 0.83 1.83 9.32 0.00 57.90 2449.83
10:18:04 PM all 10.95 0.00 20.40 0.17 1.99 8.62 0.00 57.88 2384.05
10:18:07 PM all 10.47 0.00 18.11 0.00 1.50 8.47 0.00 61.46 2416.00
10:18:10 PM all 11.81 0.00 22.63 0.00 1.83 11.98 0.00 51.75 2210.60
10:18:13 PM all 6.31 0.00 10.80 0.00 1.00 5.32 0.00 76.58 1795.33
10:18:19 PM all 1.75 0.00 3.16 0.75 0.25 1.25 0.00 92.85 1245.18
10:18:22 PM all 11.94 0.00 19.07 0.00 1.99 8.29 0.00 58.71 2630.46
10:18:25 PM all 11.65 0.00 19.30 0.50 2.00 9.15 0.00 57.40 2673.91
10:18:28 PM all 11.44 0.00 21.06 0.33 1.99 10.61 0.00 54.56 2369.87
Average: all 9.27 0.00 16.18 0.30 1.50 7.64 0.00 65.11 2173.54
The above two tables show that when you want to correctly reflect the system situation, you need to use the command parameters correctly. vmstat and iostat also need to pay attention to this issue.
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