Shulou(Shulou.com)06/02 Report--

Today, I want to share some cloud computing learning route course outline information with you. This article is about some learning notes on the use of signal control processes. I hope to give you some help:

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kill,killall,pgrep,pkill,top

Send signals to processes

[root@tianyun ~]# kill -l //List all supported signals

number signal name

1)SIGHUP reload configuration PID unchanged

2)SIGINT Keyboard Interrupt ^C

3)SIGQUIT keyboard exit

9)SIGKILL Forced Termination

15)SIGTERM terminate (normal end), default signal

18)SIGCONT Continue

19)SIGSTOP Stop

20)SIGTSTP suspended ^Z

Job 1: Signal vsftpd process1, 15

vsftpd signal test

[root@tianyun ~]# yum -y install vsftpd

[root@tianyun ~]# systemctl start vsftpd

[root@tianyun ~]# ps aux |grep vsftpd

root 9160 0.0 0.0 52580 904 ? Ss 21:54 0:00 /usr/sbin/vsftpd /etc/vsftpd/vsftpd.conf

[root@tianyun ~]# kill -1 9160 //Send a restart signal, for example, the configuration file of vsftpd has changed and you want to reload it.

root 9160 0.0 0.0 52580 904 ? Ss 21:54 0:00 /usr/sbin/vsftpd /etc/vsftpd/vsftpd.conf

[root@tianyun ~]# kill 9160 //Send stop signal, vsftpd service has stop script systemctl stop vsftpd

[root@tianyun ~]# ps aux |grep vsftpd

crond signal test

//1

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ ps aux |grep [c]rond

root 478 0.0 0.1 124144 1572 ? Ss 09:35 0:00 /usr/sbin/crond -n

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ sudo kill -1 478

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ ps aux |grep [c]rond

root 478 0.0 0.1 124144 1572 ? Ss 09:35 0:00 /usr/sbin/crond -n

//15

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ sudo kill 478

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ ps aux |grep crond

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ sudo systemctl start crond

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ ps aux |grep crond

root 22319 0.0 0.1 124140 1548 ? Ss 14:54 0:00 /usr/sbin/crond -n

Assignment 2: Signal Test 9, 15

[root@tianyun ~]# touch file1 file2

[root@tianyun ~]# tty

/dev/pts/1

[root@tianyun ~]# vim file1

[root@tianyun ~]# tty

/dev/pts/2

[root@tianyun ~]# vim file2

[root@tianyun ~]# ps aux |grep vim

root 4362 0.0 0.2 11104 2888 pts/1 S+ 23:02 0:00 vim file1

root 4363 0.1 0.2 11068 2948 pts/2 S+ 23:02 0:00 vim file2

[root@tianyun ~]# kill 4362

[root@tianyun ~]# kill -9 4363

[root@tianyun ~]# killall vim //Send a signal to all vim processes

[root@tianyun ~]# killall httpd

Assignment 3: Signal Testing 18, 19

[root@tianyun ~]# ps aux |grep sshd

root 5571 0.0 0.0 64064 1164 ? Ss 09:35 0:00 /usr/sbin/sshd

[root@tianyun ~]# kill -STOP 5571

[root@tianyun ~]# ps aux |grep sshd

root 5571 0.0 0.0 64064 1164 ? Ts 09:35 0:00 /usr/sbin/sshd

[root@tianyun ~]# kill -cont 5571

[root@tianyun ~]# ps aux |grep sshd

root 5571 0.0 0.0 64064 1164 ? Ss 09:35 0:00 /usr/sbin/sshd

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ ps aux |grep crond

root 22319 0.0 0.1 124140 1568 ? Ss 14:54 0:00 /usr/sbin/crond -n

yang 22427 0.0 0.0 112648 964 pts/2 R+ 15:07 0:00 grep --color=auto crond

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ sudo kill -19 22319

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ ps aux |grep crond

root 22319 0.0 0.1 124140 1568 ? Ts 14:54 0:00 /usr/sbin/crond -n

yang 22431 0.0 0.0 112648 964 pts/2 R+ 15:07 0:00 grep --color=auto crond

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ sudo kill -cont 22319

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ ps aux |grep crond

root 22319 0.0 0.1 124140 1568 ? Ss 14:54 0:00 /usr/sbin/crond -n

yang 22436 0.0 0.0 112648 960 pts/2 R+ 15:08 0:00 grep --color=auto crond

Assignment 4: Kicking out a user who logged in remotely

[root@tianyun ~]# pkill --help

pkill: invalid option -- '-'

Usage: pkill [-SIGNAL] [-fvx] [-n|-o] [-P PPIDLIST] [-g PGRPLIST] [-s SIDLIST]

[-u EUIDLIST] [-U UIDLIST] [-G GIDLIST] [-t TERMLIST] [PATTERN]

[root@tianyun ~]# pkill -u alice

[root@tianyun ~]# w

15:46:44 up 2:19, 4 users, load average: 0.17, 0.12, 0.08

USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT

root tty1 :0 21:32 ? 4:22 4:22 /usr/bin/Xorg :

root pts/0 :0.0 15:46 0.00s 0.00s 0.00s w

root pts/3 172.16.8.100 15:46 2.00s 0.01s 0.00s sleep 50000

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ w

15:17:25 up 5:42, 3 users, load average: 0.00, 0.01, 0.05

USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT

yang pts/0 123.120.22.32 15:00 21.00s 0.00s 0.00s -bash

yang pts/1 123.120.22.32 15:00 5.00s 0.00s 0.00s w

yang pts/2 123.120.22.32 12:04 13.00s 0.12s 0.02s vim file1

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ pkill -t pts/2 //terminate all processes on pts/2

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ pkill -9 -t pts/2 //terminate all processes on pts/2 and end the pts/2

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ w

15:20:59 up 5:45, 3 users, load average: 0.00, 0.01, 0.05

USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT

yang pts/0 123.120.22.32 15:00 3:55 0.00s 0.00s -bash

yang pts/1 123.120.22.32 15:00 3.00s 0.01s 0.00s w

yang pts/2 123.120.22.32 15:20 3.00s 0.00s 0.00s -bash

[yang@iZm5eiwihahzq6ds23gbf6Z ~]$ sudo pkill -u yang

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