Common explanations of process management under Linux

Common explanations of process management under Linux

1.init: The process number is 1, which is the main process for all processes

2.ps command: View process status command, static process state

A: All terminal-related processes

U: Details displayed by user name

x: All processes unrelated to the terminal

-E: All Processes

-L: Long format display

-F: Full output

-o: Custom format output

Common commands:

PS aux displays all processes and displays them in detail

PS aux | grep httpd filtering out HTTPD process related information

Ps-elf Show all processes and show them in detail

Ps-ef Show all processes and show them in detail

Ps-axo User,pid,comm,ni

[Email protected] sh]# Ps-axo User,pid,comm,ni

Warning:bad syntax, perhaps a bogus '-'? See/usr/share/doc/procps-3.2.7/faq

USER PID COMMAND NI

Root 1 init 0

Root 2 migration/0-

Root 3 ksoftirqd/0 19

Root 4 events/0-5

Process Status:

D: Non-disruptive sleeping uninterruptible sleep

R: Run or Ready Running

S: interruptible sleep interruptible sleeps

T: Stops stop

Z: Zombie Zombie

<: high-priority process

N: Low-priority process

+: Processes in the foreground process group

L: Multithreaded Process

S: Session process first Process

2.pstree: Displays the process tree on the current system

3.pgrep: Search process based on user name, etc.

Pgrep-u Root

4.pidof: According to the program name, find the ID number of its related process;

[Email protected] sh]# pidof httpd

1931 1850 1849 1848 1847 1846 1845

5.top command: Type in Windows Task Manager, default 5-second refresh by CPU size sort, real-time process status

M: Sort based on the size of the resident memory

P: Sort by CPU percent usage

T: Sort by cumulative time

L: Show average load and start time

T: whether to display process and CPU status related information

M: whether memory-related information is displayed

C: Whether to display full command line information

Q: Exit Top

K: Terminate a process

-D: Refers to the duration of the refresh, in seconds

Top-d 1

-B: All flip screen printing

Top-d 1-b

-N #: Turn several screens to print

Top-d 1-b-N 5

6. Interprocess communication (Ipc:inter process communication)

Format: Kill PID control or kill specified PID process number

Killall commannd control or kill a class of service processes, typically specifying the process name instead of the PID process number

Important signal: Kill-l Show All signals

1:sighup: Let a process without restarting, you can reread its configuration file, and let the new configuration information to take effect;

2:sigint:ctrl+c: Interrupts a process

9:sigkill: kills the specified process directly, regardless of the child process

15:sigterm: Terminates a process, but notifies the child process to kill first, as the default signal,

Specify a signal format:

Signal number : kill-1

Signal name : Kill-sigkill

Signal name shorthand : Kill-kill

6.1. Kill 12321 Processes directly

Kill-9 12321

6.2. Kill all httpd processes directly,

Killall-9 httpd

Note: Because the HTTPD service contains a lot of processes, if you kill the command, you will be killed many times, and Killall once

7. Adjust the nice value:

The priority of the 7.1.linux system is 0-139 priority, 0-99 of which are kernel-adjusted; 100-139 is user-controlled

7.2. The smaller the number, the higher the priority

7.3.nice Adjust priority value range 20 to 19, process default Nice value is 0,

To adjust the nice value of a process that has already started:

Renice NI PID

Specify a nice value at startup:

Nice-n NI COMMAND

8. Foreground job: Occupy command prompt

Background job: After startup, release the command prompt, and subsequent operations are completed in the background

Front-to-back switching:

CTRL + Z: Send the job at the front desk to the backstage

Command &: Let commands execute in the background

BG: Let the stop job in the background continue to run

Format: BG [[%]jobid]

Jobs: View all jobs in the background; [Job number, different from process number]

+: will be the default action of the job

-: The job that will be the second operation

FG: Back-office jobs to the foreground

Format: FG [[%]jobid]

Kill%jobid: Terminates a job, this% cannot be defaulted, otherwise conflicts with the process number

9.vmstat: System Status View command

Vmstat 1 refreshes per second

Vmstat 1 5 Refreshes once per second and displays only 5 rows

10.uptime: Display system running long and load

This article is from the "Xavier Willow" blog, please be sure to keep this source http://willow.blog.51cto.com/6574604/1767892

Common explanations of process management under Linux