RHCSA7

Linux Process introduction
process ： Started program
Process status ：stop、running、sleep
ps List the processes in the system
ps -ef
ps aux
The output of the two is not much different , But the display style is different .aux yes BSD style ,-ef yes System V style . This is a minor difference , One difference that affects use is aux Will be truncated command Column , and -ef Can't .

top Dynamic display process status （ Memory consumption is higher than others ）
It can be used ？ See sort by

Process management and performance query
Foreground process
example ：sleep 10（10s The internal front desk cannot be operated ）

Background processes
example ：
sleep 1000 &（ Create background process ）
ps -ef | grep sleep perhaps jobs
bg Process number （ Background running process ）
fg Process number （ The foreground runs the process ）

The end of the process
kill
-l Check what you can use
9 Force end process , Regardless of process status
15 The end of the process , Automatic end （ Don't write default 15）
How to write it ：kill num Process number
kill all name End all name process

pkill
-U user end user All processes
-t terminal

Load average
vmstat 2
ctrl+z

Control services and daemons
systemctl
systemctl isolate multi-user.target Enable command line interface
systemctl list-units View system services
systemctl list-units --all View all services of the system
systemctl list-units -file service

systemctl is-failed/active/enable/runing View service status
How to write it ：systemctl is-failed sshd

systemctl stop Service name
systemctl reload Service name
systemctl restart Service name
systemctl status Service name