Linux system monitoring

1 & mdash; understand the system status # uname & amp; ndash; a: displays the complete information of the system. Uname: displays the system information. Hostname: displays the host name. Last: lists the most recent user logon. Lastlog: lists the recent user logon. Free: displays the memory usage. umstart is also displayed... 1-understand the status of the system # uname-a displays the complete information of the system Uname displays the system information Hostname displays the host name Last lists the recent user logon Lastlog lists the recent logon status of each user Free displays memory usage the status of umstart is also Memory Display, but it is not free to display more detailed Top system monitor, top is the most commonly used monitoring system. top is executed in the background, but it is a bit like this: process content can be dynamically displayed on the screen, refresh the first line of Top every five seconds on the screen: It mainly displays the enabling time. several users are logged on to the host, and the average load is the second line: The third line of the current process is displayed: displays the total cpu load. the closer the id value is to the 100% table. The better the name, the less the system resources. row 4: The fifth line of memory: virtual memory. row 6: optical table. you can enter the command 1-top or add some parameters following it, for example: update it in 3 seconds # top-d 3 Top is executed twice and redirected to the current file named top. in the test file, # top-d-n 2> top # cat top1-process: all processes running on sub-linux can be called processes. The system completes the work through processes, each process has an independent process number. the system calls the process number to schedule and manipulate the process. The original process of the system is init. The PID of init is always 1. every process number of the system is unique. every process has an independent PID number. one process can generate another process, all processes except init have parent processes. Sub-process is another process generated by the parent process 1-The command ps Pstree of the process query process can be used to display the parent-child relationship of the process in a tree-like manner. Top is a common system monitoring tool. 1-Ps-A and-e display all processes.-a also displays all processes, however, only the valid-x and-a are displayed for use. The full-L mode is used in long mode, more detailed display information-f in the complete way to display information 1-ps after the plus-without-, meaning completely different, generally if you add aux, generally do not add-