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F ： The system token that the kernel assigns to a process
S ： State of process
UID ： The user who started these processes
PID ： Process of process ID, Every process has a unique PID
PPID ： The process number of the parent process （ If the process is started by another process ）
C ： In the life cycle of a process CPU utilization
PRI ： Priority of the process （ The higher the number, the lower the priority ）
NI ： Humility value is used to participate in determining priority
ADDR ： The memory address of the process
SZ ： If the process is called , The approximate size of the swap space required
WCHAN： If the process is dormant , The system function name in sleep is displayed
STIME： System time when the process started
TTY ： The terminal device when the process starts
TIME ： The cumulative amount required to run the process CPU Time
CMD ： The start command of the process

add grep You can check whether the program is running

TOP command

View process dynamic information

Express meaning

start ：
8:59:15 ： Current time
up 21min ： The time the system runs
1 user ： Number of current login users
load average ： System load , The average length of the task queue . The three are 1min ,5min ,15min
The average from minutes ago to now
Tasks ： System task information ：total The total number of processes ;running, Number of running processes ;
sleeping Number of dormant processes ;stopped Number of processes aborted ;zombie The number of dead and unresponsive processes
%CPU Occupancy information ：us User occupied ;sy Kernel occupancy ;ni Priority scheduling occupies ;id Free CPU;wa I/O Waiting for occupation
hi Hardware interrupt occupation ;si Software interrupt occupancy ;st Virtualization takes up .
KiB Mem Memory ：total Total memory space ;free Free memory ;used Used memory ;buff/cache Physical memory and swap Total number of stored buffers .
KiB Swap ：total Total swap space ;free Space exchange space ;used Used swap space ;avail Mem Available physical space

PID ： process ID
USER ： User name of the process owner
PR ： priority
NI ： Humility value Negative value indicates high priority , A positive value indicates a low priority
VIRT ： Total virtual memory used by the process , Company kb
RES ： The amount of physical memory used by the process , Company kb
SHR ： Shared memory size , Company kb
S ： Process status
%CPU ： Last updated to now CPU Percentage of time used
%MEM : Percentage of physical memory used by the process
TIME : Used by process CPU The sum of time , Company 1/100 second
COMMAND： Command name , Command line

top Shortcut keys of full screen operation interface

s ： Change the refresh time , Press space to refresh immediately Default 3s Refresh once

p ： Press CPU Sort

M ： Sort by memory

T ： Sort by time

P ： process IP, Check the status of a process

N ： Sort according to startup time

1 : Show the... For each kernel CPU Usage rate u/U： Specify the user to display

h ： You can get top Online help information for the program

q : sign out

pgrep command

-l ： At the same time, output the corresponding process name and PID
-U ： Query the process of a specific user
-t ： Designated terminal

pstree command

View the process tree

-p ： You can list the corresponding PID Number
-u ： You can list the corresponding user names
-a ： You can list complete command information

Control process

The process startup mode is manual startup and scheduling startup

Manual start

The front desk starts ： The user enters the command , Direct execution of the program

Background start ： In the command At the end of the line Join in “&” Symbol （ The reason for putting it in the background is that some programs are relatively large , May not finish , So it should be run in the background , In this way, other operations can be carried out at the same time .）

Restore the background process
bg ： You can resume the task of the command suspended in the background , Continue to execute in the background
fg ： You can restore the background task to the foreground .
CTRL+Z You can put the task in the background and pause

jobs

View the list of tasks in the background

-l The process can be displayed at the same time

kill

The specified information can be sent to the program

1 (HUP)： Reload process .
9 (KILL)： Kill a process .
15 (TERM)： Normally stop a process .（ The default value is ）

killall command

Terminate the process by its name

When the system needs to end multiple processes with the same name , This command is much more convenient

Can directly kill all at the same time vim The process of

pkill command

According to the name of the process 、 The user running the process 、 The terminal where the process is located, etc. to end the process
-U ： Designated user
-t ： Designated terminal

for example

pgerp -l -U “zhangsan” Find out the process of user Zhang San
pkill -9 -U “zhangsan” Specify the user to kill the process

Planning task management

at

date Display current time
at 16:10 ( Only write the time to indicate the day )
enter
Then write down the commands that need to be executed And then go back
ctrl+d Submit run ctrl+c Exit not run

crontab command

According to the preset time period （ Time sharing day month week ） Repeat the user specified command operation
It belongs to periodic tasks

-e Start planning tasks
-l View scheduled tasks
-r Delete scheduled task

View relevant configuration files

Special representation of time value

* This is an arbitrary range of time
, Represents multiple discontinuous time points of an interval
- Represents a continuous time range
/ Specify the time and frequency of the interval

minute ：0-59
Hours ：0-23
date ：1-31
month ：1-12
week ：0-7（0 and 7 It means Sunday ）