Ubuntu系统网络配置总结、shell脚本示例

1、Ubuntu系统网络配置总结（包括主机名、网卡名称、网卡配置）

1.1 主机名

修改主机名和centos7一样修改后永久生效

root@ubuntu:~# hostnamectl set-hostname ubuntu2004.waluna.top
root@ubuntu:~# cat /etc/hostname 
ubuntu2004.waluna.top
root@ubuntu:~# hostname
ubuntu2004.waluna.top
root@ubuntu:~# echo $HOSTNAME
ubuntu
root@ubuntu:~# exit
logout
ubuntu@ubuntu:~$ sudo -i  
root@ubuntu2004:~# echo $HOSTNAME
ubuntu2004.waluna.top

1.2 网卡名称

默认ubuntu的网卡名称和centos7类似，如：ens33，ens38等

修改网卡名称为传统命名方式：

# 修改配置文件为下面形式
root@ubuntu2004:~# vim /etc/default/grub
GRUB_CMDLINE_LINUX="net.ifnames=0"
# 或者sed修改
root@ubuntu2004:~# sed -i.bak '/^GRUB_CMDLINE_LINUX=/s#"$#net.ifnames=0"#' /etc/default/grub

# 生效新的grub.cfg文件
root@ubuntu2004:~# grub-mkconfig -o /boot/grub/grub.cfg 
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-112-generic
Found initrd image: /boot/initrd.img-4.15.0-112-generic
done
# 或者
root@ubuntu2004:~# update-grub
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-112-generic
Found initrd image: /boot/initrd.img-4.15.0-112-generic
done
root@ubuntu2004:~# grep net.ifnames /boot/grub/grub.cfg 
        linux   /boot/vmlinuz-4.15.0-112-generic root=UUID=eb982e5d-8588-4714-92ac-bb09908d16c8 ro net.ifnames=0 
                linux   /boot/vmlinuz-4.15.0-112-generic root=UUID=eb982e5d-8588-4714-92ac-bb09908d16c8 ro net.ifnames=0 
                linux   /boot/vmlinuz-4.15.0-112-generic root=UUID=eb982e5d-8588-4714-92ac-bb09908d16c8 ro recovery nomodeset net.ifnames=0

# 重启生效
root@ubuntu2004:~# reboot

1.3 网卡配置

1.3.1 配置自动获取IP

网卡配置文件才用YAML格式，必须以/etc/netplan/xxx.yaml文件命名方式存放

可以每个网卡对应一个单独的配置文件，也可以将所有网卡都放在一个配置文件里

root@ubuntu2004:~# cat /etc/netplan/01-netcfg.yaml 
# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      dhcp4: yes

修改网卡配置文件后需执行命令生效：

root@ubuntu2004:~# netplan apply

1.3.2 配置静态IP

root@ubuntu2004:~# cat /etc/netplan/01-netcfg.yaml
# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      addresss: [192.168.8.10/24,10.0.0.10/8]   # 或者用下面两行，两种格式不能混用
        - 10.0.0.129/24
        - 192.168.8.10/24
      gateway4: 10.0.0.2
      nameservers:
        search: [waluna.top,waluna.xyz]
        addresses: [114.114.114.114,8.8.8.8]

查看IP和gateway

root@ubuntu2004:~# ip addr
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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:93:a6:2e brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.129/24 brd 10.0.0.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe93:a62e/64 scope link 
       valid_lft forever preferred_lft forever
root@ubuntu2004:~# route -n 
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    0      0        0 eth0
10.0.0.0        0.0.0.0         255.255.255.0   U     0      0        0 eth0

查看DNS

root@ubuntu2004:~# ls -l /etc/resolv.conf 
lrwxrwxrwx 1 root root 39 Mar 17 02:37 /etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf
root@ubuntu2004:~# systemd-resolve --status 
Global
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 2 (eth0)
      Current Scopes: DNS
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: 114.114.114.114
                      8.8.8.8

2、编写脚本实现登陆远程主机（使用expect和shell脚本两种形式）

# 最小化安装需要安装expect工具
[root@centos8 ~]# dnf install expect -y

# 利用ssh远程登录到10.0.0.7
[root@centos8 ~]# rm -rf .ssh/ 
[root@centos8 ~]# cat expect1
#!/usr/bin/expect   # 注意shebang要用#!/usr/bin/expect
spawn ssh 10.0.0.7
expect {
    "yes/no" { send "yes\n";exp_continue }
    "password" { send "waluna\n"}
}
expect eof
[root@centos8 ~]# chmod +x expect1  # 不是bash脚本，只能加执行权限
[root@centos8 ~]# ./expect1
spawn ssh 10.0.0.7
The authenticity of host '10.0.0.7 (10.0.0.7)' can't be established.
ECDSA key fingerprint is SHA256:BvEOFVidIWSNe478SZ34jegCVOHesBaPh7bWvtccBkU.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.0.0.7' (ECDSA) to the list of known hosts.
root@10.0.0.7's password: 
Last login: Sat Jun 26 21:32:12 2021 from 10.0.0.8
[root@centos7 ~]# 

# expect变量
[root@centos8 ~]# rm -rf .ssh/
[root@centos8 ~]# cat expect2  
#!/usr/bin/expect
set ip 10.0.0.7
set user root
set password waluna
spawn ssh $user@$ip
expect {
        "yes/no" { send "yes\n";exp_continue }
        "password" { send "$password\n"}
}
interact 
[root@centos8 ~]# chmod +x expect2
[root@centos8 ~]# ./expect2
spawn ssh root@10.0.0.7
The authenticity of host '10.0.0.7 (10.0.0.7)' can't be established.
ECDSA key fingerprint is SHA256:BvEOFVidIWSNe478SZ34jegCVOHesBaPh7bWvtccBkU.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.0.0.7' (ECDSA) to the list of known hosts.
root@10.0.0.7's password: 
Last login: Sat Jun 26 21:39:13 2021 from 10.0.0.8
[root@centos7 ~]# exit
logout
Connection to 10.0.0.7 closed.

# expect位置变量
[root@centos8 ~]# rm -rf .ssh/
[root@centos8 ~]# cat expect3
#!/usr/bin/expect
set ip [lindex $argv 0]
set user [lindex $argv 1]
set password [lindex $argv 2]
spawn ssh $user@$ip
expect {
        "yes/no" { send "yes\n";exp_continue }
        "password" { send "$password\n"}
}
interact
[root@centos8 ~]# chmod +x expect3
[root@centos8 ~]# ./expect3 10.0.0.7 root waluna
spawn ssh root@10.0.0.7
The authenticity of host '10.0.0.7 (10.0.0.7)' can't be established.
ECDSA key fingerprint is SHA256:BvEOFVidIWSNe478SZ34jegCVOHesBaPh7bWvtccBkU.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.0.0.7' (ECDSA) to the list of known hosts.
root@10.0.0.7's password: 
Last login: Sat Jun 26 21:40:25 2021 from 10.0.0.8
[root@centos7 ~]# exit
logout
Connection to 10.0.0.7 closed.

# shell脚本调用expect
[root@centos8 ~]# rm -rf .ssh/
[root@centos8 ~]# cat expect.sh
#!/bin/bash
ip=$1
user=$2
password=$3
expect <<EOF
set timeout 20
spawn ssh $user@$ip
expect {
    "yes/no" { send "yes\n";exp_continue }
    "password" { send "$password\n"}
}
expect eof
EOF
[root@centos8 ~]# bash expect.sh 10.0.0.7 root waluna
spawn ssh root@10.0.0.7
The authenticity of host '10.0.0.7 (10.0.0.7)' can't be established.
ECDSA key fingerprint is SHA256:BvEOFVidIWSNe478SZ34jegCVOHesBaPh7bWvtccBkU.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.0.0.7' (ECDSA) to the list of known hosts.
root@10.0.0.7's password: 
Last login: Sat Jun 26 21:59:33 2021 from 10.0.0.8
[root@centos7 ~]#

3、生成10个随机数保存于数组中，并找出其最大值和最小值

[root@centos8 ~]# cat array.sh
#!/bin/bash
declare -i min max
declare -a nums
for((i=0;i<10;i++));do
    nums[$i]=$RANDOM
    [ $i -eq 0 ] && min=${nums[0]} && max=${nums[0]} && continue
    [ ${nums[$i]} -gt $max ] && max=${nums[$i]} && continue
    [ ${nums[$i]} -lt $min ] && min=${nums[$i]}
done
echo "All numbers are ${nums[*]}"
echo MAX is $max
echo MIN is $min
[root@centos8 ~]# bash array.sh
All numbers are 13012 7448 7543 3514 15786 6363 2398 5646 12774 6680
MAX is 15786
MIN is 2398

4、输入若干个数值存入数组中，采用冒泡算法进行升序或降序排序

[root@centos8 ~]# cat bubbile.sh
#!/bin/bash
read -p "请输入数值的个数：" n
declare -i max min
declare -a nums nums1
for((i=0;i<$n;i++));do
    nums[$i]=$RANDOM
done
echo "排序前：${nums[*]}"
for((j=0;j<n;j++));do
    for((k=0;k<`echo ${#nums[*]}`;k++));do
        [ $k -eq 0 ] && min=${nums[0]} && continue
        [ ${nums[$k]} -lt $min ] && min=${nums[$k]}
    done
    nums1[$j]=$min
    nums=(${nums[*]/$min})
done
echo "排序后：${nums1[*]}"
[root@centos8 ~]# bash bubbile.sh
请输入数值的个数：7
排序前：22651 6839 6230 14934 27000 29716 27821
排序后：6230 6839 14934 22651 27000 27821 29716

5、显示统计占用系统内存最多的进程，并排序。

[root@centos8 ~]# ps axo %mem,cmd k -%mem|head
%MEM CMD
 3.5 /usr/libexec/platform-python -Es /usr/sbin/tuned -l -P
 2.9 /usr/lib/polkit-1/polkitd --no-debug
 2.5 /usr/sbin/NetworkManager --no-daemon
 2.4 /usr/libexec/sssd/sssd_nss --uid 0 --gid 0 --logger=files
 1.7 /usr/libexec/sssd/sssd_be --domain implicit_files --uid 0 --gid 0 --logger=files
 1.7 /usr/sbin/sssd -i --logger=files
 1.4 /usr/lib/systemd/systemd-udevd
 1.3 /usr/lib/systemd/systemd --switched-root --system --deserialize 17
 1.2 /usr/bin/VGAuthService -s

[root@centos8 ~]# ps axo %mem,cmd --sort -%mem|head
%MEM CMD
 3.5 /usr/libexec/platform-python -Es /usr/sbin/tuned -l -P
 2.9 /usr/lib/polkit-1/polkitd --no-debug
 2.5 /usr/sbin/NetworkManager --no-daemon
 2.4 /usr/libexec/sssd/sssd_nss --uid 0 --gid 0 --logger=files
 1.7 /usr/libexec/sssd/sssd_be --domain implicit_files --uid 0 --gid 0 --logger=files
 1.7 /usr/sbin/sssd -i --logger=files
 1.4 /usr/lib/systemd/systemd-udevd
 1.3 /usr/lib/systemd/systemd --switched-root --system --deserialize 17
 1.2 /usr/bin/VGAuthService -s

[root@centos8 ~]# ps axo %mem,cmd --sort=-%mem|head
%MEM CMD
 3.5 /usr/libexec/platform-python -Es /usr/sbin/tuned -l -P
 2.9 /usr/lib/polkit-1/polkitd --no-debug
 2.5 /usr/sbin/NetworkManager --no-daemon
 2.4 /usr/libexec/sssd/sssd_nss --uid 0 --gid 0 --logger=files
 1.7 /usr/libexec/sssd/sssd_be --domain implicit_files --uid 0 --gid 0 --logger=files
 1.7 /usr/sbin/sssd -i --logger=files
 1.4 /usr/lib/systemd/systemd-udevd
 1.3 /usr/lib/systemd/systemd --switched-root --system --deserialize 17
 1.2 /usr/bin/VGAuthService -s

6、编写脚本，使用for和while分别实现192.168.0.0/24网段内，地址是否能够ping通，若ping通则输出"success!"，若ping不通则输出"fail!"

# for循环
[root@centos8 ~]# cat for_ip.sh
#!/bin/bash
host=192.168.0.
for i in {0..255};do
    {
    ping -c1 -w1 ${host}$i &> /dev/null && echo "success!" || echo "fail!"
    }&
done
wait
[root@centos8 ~]# bash for_ip.sh
fail!
success!
success!
success!
fail!
...省略...

# while循环
[root@centos8 ~]# cat while_ip.sh
#!/bin/bash
host=192.168.0.
i=0
while ((i<=255));do
    {
    ping -c1 -w1 ${host}$i &> /dev/null && echo "${host}$i success!" || echo "fail!"
    }&
    let i++
done
wait
[root@centos8 ~]# bash while_ip.sh
[root@centos8 ~]# bash while_ip.sh 
success!
success!
success!
fail!
fail!
...省略...

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Comments | 2 条评论

博主 14660463

回复

发布于 2021-07-04 06:46 ( Google Chrome 90.0.4430.93 Windows 10 )( ) 来自: 江苏省南京市电信

命令用的很6啊！脚本写的也不错，继续加油！
- 博主 Xan_Yum
  
  回复
  
  发布于 2021-07-04 06:52 ( Google Chrome 91.0.4472.124 Windows 10 )( ) 来自: 山东省莱芜市联通
  
  @14660463 还好这次没翻车