Linux系统重要文件介绍与配置
一网卡配置文件
（一）网卡配置文件参数介绍
文件路径信息：/ec/sysconfig/network-scripts/ifcfg-eth0
文件作用说明：配置网卡地址信息（IP地址掩码地址网关地址DNS地址信息）
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eth0
UUID=9d9e2656-f3ac-4f75-8722-3136d239985d
DEVICE=eth0
ONBOOT=yes
IPADDR=10.0.0.200
PREFIX=24
GATEWAY=10.0.0.254
IPV6_PRIVACY=no
DNS1=223.5.5.5
TYPE=Ethernet 指定网络类型——以太网类型
3G、4G、5G--人工智能自动驾驶
DEFROUTE=yes---是否激活默认路由（网络知识会说）
NAME=eth0---网卡名称信息，逻辑名称
DEVICE=eth0--网卡名称信息，设备名称
UUID=9d9e2656-f3ac-4f75-8722-3136d239985d eth0网卡设备编号
逻辑名称和设备名称的区别？
快速修改IP地址
[root@centos7 ~]# sed -i s/200/201/g /etc/sysconfig/network-scripts/ifcfg-eth0
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eth0
UUID=9d9e2656-f3ac-4f75-8722-3136d239985d
DEVICE=eth0
ONBOOT=yes
IPADDR=10.0.0.201
PREFIX=24
GATEWAY=10.0.0.254
IPV6_PRIVACY=no
DNS1=223.5.5.5
[root@centos7 ~]# service network restart
Restarting network (via systemctl):
（二）网卡配置文件生效
方法一：利用systemctl命令 systemctl restart network 企业环境不建议
方法二：利用service命令 service network restart 企业环境不建议
方法三：利用ifxx命令，指定网卡重启 ifdown eth0 && ifup eth0 企业环境配置，建议使用
（三）修改网卡名称信息
（1）修改网卡文件中名称信息
vi ifcfg-ens33
NAME=eth0
DEVICE=etho
[root@centos72 ~]# sed -i s/ens33/eth0/g /etc/sysconfig/network-scripts/ifcfg-ens33
[root@centos72 ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eth0
UUID=faef9329-c9bb-4ba8-84d9-853c3409bb2e
DEVICE=eth0
ONBOOT=yes
IPADDR=10.0.0.72
GATEWAY=10.0.0.1
NETMASK=255.255.255.0
DNS1=223.5.5.5
DNS2=8.8.8.8
（2）网卡文件名称重命名
[root@centos72 ~]# mv /etc/sysconfig/network-scripts/ifcfg-ens33 /etc/sysconfig/network-scripts/ifcfg-eth0
（3）让系统内核加载网卡名称修改信息
[root@centos72 ~]#vim /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet net.ifnames=0 biosdevname=0"
GRUB_DISABLE_RECOVERY="true"
~
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~
~
~
~
~
~
~
~
~
~
~
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"/etc/default/grub" 7L, 247C written
[root@centos72 ~]# cat /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rhgb quiet net.ifnames=0 biosdevname=0"
GRUB_DISABLE_RECOVERY="true"
（4）加载修改配置信息
grub2-mkconfig -o /boot/grub2/grub.cfg
[root@centos72 ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-1062.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-1062.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-cb26ac281315402a9928e9a4c3bedfcd
Found initrd image: /boot/initramfs-0-rescue-cb26ac281315402a9928e9a4c3bedfcd.img
done
（5）重启操作系统
reboot
[root@centos72 ~]# reboot
Connection closed by foreign host.
Disconnected from remote host(10.0.0.72:22) at 11:23:14.
Type `help' to learn how to use Xshell prompt.
[c:~]$ ssh 10.0.0.72
Connecting to 10.0.0.72:22...
Connection established.
To escape to local shell, press Ctrl+Alt+].
WARNING! The remote SSH server rejected X11 forwarding request.
Last login: Mon Dec 2 11:15:23 2019 from 10.0.0.1
[root@centos72 ~]# mv /etc/sysconfig/network-scripts/ifcfg-ens33 /etc/sysconfig/network-scripts/ifcfg-eth0^C
[root@centos72 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:fc:69:f8 brd ff:ff:ff:ff:ff:ff
inet 10.0.0.72/24 brd 10.0.0.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::6a03:a879:3759:698a/64 scope link noprefixroute
valid_lft forever preferred_lft forever
二域名服务配置文件
文件路径信息：/etc/resolv.conf
文件作用说明：访问名称或者域名信息
vi /etc/resolv.conf
nameserver 223.5.5.5（DNS服务器地址）
PS:DNS服务器将域名解析成IP地址
223.5.5.5 阿里云公司
114.114.114.114 电信公司
[root@centos7 ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search com
nameserver 223.5.5.5
注意我在北方，所以不能ping通114.114.114.114
[root@centos7 ~]# ping 114.114.114.114
PING 114.114.114.114 (114.114.114.114) 56(84) bytes of data.
^C
--- 114.114.114.114 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 2999ms
[root@centos7 ~]# ping 223.5.5.5
PING 223.5.5.5 (223.5.5.5) 56(84) bytes of data.
64 bytes from 223.5.5.5: icmp_seq=1 ttl=128 time=58.8 ms
64 bytes from 223.5.5.5: icmp_seq=2 ttl=128 time=58.3 ms
64 bytes from 223.5.5.5: icmp_seq=3 ttl=128 time=56.9 ms
^C
--- 223.5.5.5 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2004ms
rtt min/avg/max/mdev = 56.928/58.057/58.856/0.820 ms
三本地域名解析文件
文件路径信息：/etc/hosts
文件作用说明：实现本地名称解析（用于访问不同服务器）用于网站测试
web服务器、数据库服务器、存储服务器、监控服务器、日志服务器、备份服务器、审计服务器、缓存服务器器
相当于公司的各个职位：销售、行政、运营
上面在架构里面出现，需要通过网络进行交流
[root@centos7 ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
web服务器——网络——数据库服务器192.173.16.122 dbe1， 存储服务器187.169.45.231 date01，监控服务器177 187 56 937abbix01
注意本地的域名解析优先级更高
[root@centos7 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:ea:b8:14 brd ff:ff:ff:ff:ff:ff
inet 10.0.0.200/24 brd 10.0.0.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::951a:d6ce:9fbd:c7b7/64 scope link noprefixroute
valid_lft forever preferred_lft forever
[root@centos7 ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
10.0.0.200 www.baidu.com
[root@centos7 ~]# ping www.baidu.com
PING www.baidu.com (10.0.0.200) 56(84) bytes of data.
64 bytes from www.baidu.com (10.0.0.200): icmp_seq=1 ttl=64 time=0.058 ms
64 bytes from www.baidu.com (10.0.0.200): icmp_seq=2 ttl=64 time=0.040 ms
64 bytes from www.baidu.com (10.0.0.200): icmp_seq=3 ttl=64 time=0.042 ms
^C
--- www.baidu.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.040/0.046/0.058/0.011 ms
四开机自动运行命令文件
文件路径信息：/etc/rc.local
文件作用：让系统启动后，自动运行命令信息文件内容信息：#！/bin/bash脚本文件
PS：确认/etc/rc.d/rc.local文件必须有执行权限
chmod +x /etc/rc.d/rc.local
脚本文件：将复杂工作简单化将重复工作高效化堆命令文件脚本文件如何执行：
方法一：
sh 脚本文件.sh
方法二：
必须确认脚本文件有执行权限
x--execute脚本文件.sh
需求：系统启动好
文件内容信息：
1）将重要数据做好初始备份
2）系统启动好自动清除回收站数据
3）实现自动存储设备挂载
[root@centos7 ~]# ll /etc/rc.local
lrwxrwxrwx. 1 root root 13 Nov 26 17:33 /etc/rc.local -> rc.d/rc.local
[root@centos7 ~]# ll rc.d/rc.local
ls: cannot access rc.d/rc.local: No such file or directory
[root@centos7 ~]# ll /root/rc.d/rc.local
ls: cannot access /root/rc.d/rc.local: No such file or directory
[root@centos7 ~]# ll /etc/rc.d/rc.local
-rw-r--r--. 1 root root 579 Dec 2 12:39 /etc/rc.d/rc.local
[root@centos7 ~]# chmod +x /etc/rc.d/rc.local
[root@centos7 ~]# ll /etc/rc.d/rc.local
-rwxr-xr-x. 1 root root 579 Dec 2 12:39 /etc/rc.d/rc.local
[root@centos7 ~]# cat /etc/rc.local
#!/bin/bash
# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
#
# It is highly advisable to create own systemd services or udev rules
# to run scripts during boot instead of using this file.
#
# In contrast to previous versions due to parallel execution during boot
# this script will NOT be run after all other services.
#
# Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure
# that this script will be executed during boot.
mkdir -p /backup
cp /etc/hosts /backup
rm -rf /tmp/*
mount /dev/cdrom /mnt
touch /var/lock/subsys/local