笺注:这是在 CentOS8编译安装Zabbix4.4.5 的基础上进行的。
检测防火墙服务firewalld是否运行中:
方法一:(要按“q”键退出)
systemctl status firewalld
方法二:
[root@centos8 ~]# systemctl | grep firewalld
firewalld.service loaded active running firewalld - dynamic firewall daemon
[root@centos8 ~]#
[root@centos8 ~]# echo $?
0
注释:返回值为0时,才代表True
方法三:
[root@centos8 ~]# ps -ef |grep firewalld
root 970 1 0 17:16 ? 00:00:00 /usr/libexec/platform-python -s /usr/sbin/firewalld --nofork --nopid
root 2249 2189 0 17:27 pts/1 00:00:00 grep --color=auto firewalld
[root@centos8 ~]#
[root@centos8 ~]# echo $?
0
[root@centos8 ~]# ps -ef |grep firewalld |grep -v grep
root 970 1 0 17:16 ? 00:00:00 /usr/libexec/platform-python -s /usr/sbin/firewalld --nofork --nopid
[root@centos8 ~]#
[root@centos8 ~]# echo $?
0
停止服务firewalld:
[root@centos8 ~]# systemctl stop firewalld
服务firewalld停止后的效果:
[root@centos8 ~]# systemctl | grep firewalld
[root@centos8 ~]#
[root@centos8 ~]# echo $?
1
[root@centos8 ~]# ps -ef |grep firewalld
root 2338 2189 0 17:30 pts/1 00:00:00 grep --color=auto firewalld
[root@centos8 ~]# echo $?
0
[root@centos8 ~]#
[root@centos8 ~]# ps -ef |grep firewalld |grep -v grep
[root@centos8 ~]#
[root@centos8 ~]# echo $?
1
启动服务firewalld:
[root@centos8 ~]# systemctl start firewalld
重启服务firewalld:
[root@centos8 ~]# systemctl restart firewalld
查看服务firewalld是否开机自动启动:(服务firewalld默认就是开机自动启动)
[root@centos8 ~]# systemctl is-enabled firewalld
enabled
查看开机自动启动的服务的列表:(截图有省略)
systemctl list-unit-files|grep enabled
禁止开机时自动启动服务firewalld:
[root@centos8 ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@centos8 ~]# systemctl is-enabled firewalld
disabled
查看开机时不可自动启动的服务的列表:(截图有省略)
systemctl list-unit-files|grep disabled
开机时自动启动服务firewalld:
[root@centos8 ~]# systemctl enable firewalld
Created symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service → /usr/lib/systemd/system/firewalld.service.
Created symlink /etc/systemd/system/multi-user.target.wants/firewalld.service → /usr/lib/systemd/system/firewalld.service.
######
使用命令netstat检测本机的某个端口是否运行中
检测TCP 80端口是否运行中:
[root@centos8 ~]# netstat -anp | grep 80
-bash: netstat: 未找到命令
注释:最小化安装是没有命令netstat
安装相关软件包:
[root@centos8 ~]# dnf -y install net-tools
启动MariaDB:
[root@centos8 ~]# systemctl start mysqld
检测TCP 3306端口是否运行中:
[root@centos8 ~]# netstat -anp | grep 3306
tcp6 0 0 :::3306 :::* LISTEN 1103/mysqld
[root@centos8 ~]# echo $?
0
注释:返回值为0时,才代表True
命令netstat也可以检测服务是否在运行中:
netstat -anp | grep mysqld
[root@centos8 ~]# netstat -anp | grep mysqld > /dev/null
[root@centos8 ~]# echo $?
0
关闭MariaDB:
[root@centos8 ~]# systemctl stop mysqld
[root@centos8 ~]# netstat -anp | grep 3306
[root@centos8 ~]#
[root@centos8 ~]# echo $?
1
[root@centos8 ~]# netstat -anp | grep mysqld
[root@centos8 ~]#
[root@centos8 ~]# echo $?
1
######
开机自动执行某些命令:
[root@centos8 ~]# vi /etc/rc.local
在末尾追加自定义的命令:(服务器重启后,无论系统用户root登录与否,命令都会执行)
echo 'Welcome to zhuohua' > /zhuohua.txt
如下图:
cat /etc/rc.local
cat /etc/rc.d/rc.local
[root@centos8 ~]# ll /etc/rc.local
lrwxrwxrwx. 1 root root 13 4月 24 2020 /etc/rc.local -> rc.d/rc.local
笺注:
/etc/rc.local 是/etc/rc.d/rc.local的链接文件;
/etc/rc.local 的默认权限是777
/etc/rc.d/rc.local 的默认权限是644
若不先给予/etc/rc.d/rc.local执行的权限,CentOS7/8不会开机自动执行/etc/rc.local里的命令:
[root@centos8 ~]# chmod a+x /etc/rc.d/rc.local
[root@centos8 ~]# ll /etc/rc.d/rc.local
-rwxr-xr-x. 1 root root 590 1月 17 21:55 /etc/rc.d/rc.local
CentOS8重启系统:
[root@centos8 ~]# which init
/usr/sbin/init
[root@centos8 ~]#
[root@centos8 ~]# init 6
服务器重启后,文件自动创建了:
[root@centos8 ~]# ll /*.txt
-rw-r--r-- 1 root root 19 1月 17 22:05 /zhuohua.txt
[root@centos8 ~]# cat /zhuohua.txt
Welcome to zhuohua
CentOS8关闭系统:
[root@centos8 ~]# init 0
相关文章:
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Xshell4远程管理CentOS8
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