Linux System Resource View

1.
Vmstat is an abbreviation for virtual meomory Statistics (dummy memory statistics) that monitors the operating system's virtual memory, process, IO read-write, CPU activity, and so on. It is the overall situation of the system statistics, the disadvantage is that a process can not be in-depth analysis.
Grammar:Vmstat [Refresh Time] [number of refreshes]

2.
The DMESG command is used to display the boot information.
The kernel will store the boot information in the ring buffer. If you are too late to view the information, you can use DMESG to view it.The boot information is also stored in the/VAR/LOG/DMESG.

3.
The free command is used to display memory status.
The free instruction shows memory usage, including physical memory, virtual swap file memory, shared memory segments, and buffers used by the system core.

-B Displays memory usage in bytes.
-K displays memory usage in kilobytes.
-m displays memory usage in megabytes.
-O does not display buffer throttling columns.
-s< interval seconds > Continuous observation of memory usage.
-T displays the memory sum column.
-V Displays version information.

4.
The uptime command is capable of printing how long the system has been running and the average load on the system. The uptime command can display information such as the current time, how long the system has been running, how many users are currently logged in, the average load of the system in the past 1 minutes, 5 minutes, and 15 minutes.can be understood as a simple version of top!

5.
The uname command is used to display system information, and uname can display information about the computer and the operating system.
Example, uname-a

6.
The Lsb_release command in Linux is used to view the distribution information for the current system. The LSB is the abbreviation for Linux Standard base, and thelsb_release command is used to display information about LSB and specific versions. If the command is used without parameters, the default is the-v parameter. With this command you can clearly know whether the redhat, or other distributions, there is a specific version number, such as 3.4 or 5.4 and so on. Some systems do not necessarily have this command installed, and you can get the release information by looking at the /etc/issue file.
-V Displays version information.

-I displays the ID of the release version .

-D Displays the description of the release.

-R shows the current system is the specific version number of the release version.

-C Release version code.

　　 -A displays all information above.

-h Displays help information.

7.
Lsof The Open file (lists openfiles) is listed. And one thing to keep in mind is that everything in Unix, including the network socket interface, is a file.

Lsof lists the files that the process opens or uses.

example, Lsof-c < process number > ===> lists all files opened by the process

Lsof-u <uid/User name > ===> to change all files opened by the user

Lsof/sbin/init ===> displays all files opened with the specified directory

Lsof-c httpd ===> View all files used by the httpd process

Lsof-c 0 or losf-c root ===> view all files used by the root user

Xiao Kee:

① Many of the service names in Linux are httpd,vsftpd,atd and so on, where "D" means---daemon (daemon).
②file/bin/ls "/bin/ls" can be replaced by any command, which can be used to view the number of bits of the Linux operating system.

Linux System Resource View