ps
ps process viewing command, providing viewing, running status of the process, occupied resources and other information
ps only view the instantaneous status of the current process, not dynamic and continuous; (real-time monitoring commandtop)
parameter
-A: All processes are displayed, which has the same effect as -e;
-a: All processes under the current terminal, including processes of other users;
-u: User-based process status;
x: Usually used with the a parameter, More complete information can be listed.
l: Longer and more detailed information about the PID is listed;
j: Jobs format
-f: Do a more complete output.
FRepresents the flag of this program (flag), 4 represents the user is superuser (super user);
Srepresents the state of this program (STAT);
UIDrepresents the identity of the executor
PIDProcess ID number! The PPID at the bottom is the ID of the parent process;
USER: Which user account does this process belong to?
CPercentage
%CPUof CPU resources used: The percentage of CPU resources used by
%MEMthe process; : The percentage of physical memory occupied by the
VSZprocess; : The amount of virtual memory used by the process (Kbytes)
RSS: The fixed amount of memory (Kbytes)
TIMEused by the process lost CPU time.
SZThe amount of memory used;
PRIRefers to the execution priority of the process (abbreviation for Priority), the smaller the value, the earlier it will be executed;
NIthe nice value of this process, which represents the revised value of the priority of the process that can be executed.
ADDRThis is a kernel function that indicates which part of memory the program is in. If it is an executing program, it is generally "-"
WCHANwhether the program is currently running, if it is - it means it is running;
TTY: The process is running on the terminal. If it has nothing to do with the terminal, it will display ?. In addition, tty1-tty6 are the login programs on the local machine. If it is pts/0, etc., it means that it is connected by the network. into the host program.
STAT: The current state of the program, the main states are:
1. `R` ：该程序目前正在运作，或者是可被运作；
2. `S` ：该程序目前正在睡眠当中 (可说是 idle 状态啦！)，但可被某些讯号(signal) 唤醒。
`T` ：该程序目前正在侦测或者是停止了；
`Z` ：该程序应该已经终止，但是其父程序却无法正常的终止他，造成 zombie (疆尸) 程序的状态START: The time when the process is triggered to start;
TIME: The time when the process actually uses the CPU.
CMDName of command given
COMMAND: What is the actual command of the program?
common way
ps -lDisplay the PID and related information of this login Display the PID and related information
ps -lAof all programs
ps auxList all currently running programs in memory
ps -axjfList the program tree form
[reference document]