练习案例

1. for创建20用户

用户前缀由用户输入
用户初始密码由用户输入
例如：test01,test10

#!/bin/bash
#########################
#File name:userCreate.sh
#Version:v1.0
#Email:admin@test.com
#Created time:2023-01-03 15:48:18
#Description:
#########################
read -p "please input your username:" username
read -p "please input your userpasswd:" userpasswd

for i in {01..20}
do
        user=$username$i
        if ! id -u $user &>/dev/null
        then
                useradd $user
                echo $userpasswd | passwd  --stdin $user &>/dev/null
        else
                echo "then user is exists..."
        fi
done

运行结果

[root@localhost homework4]# bash userCreate.sh
please input your username:xixi
please input your userpasswd:123
[root@localhost homework4]# cat /etc/passwd

2. for ping测试指网段的主机

网段由用户输入，例如用户输入192.168.2 ，则ping 192.168.2.10 — 192.168.2.20
UP： /tmp/host_up.txt
Down: /tmp/host_down.txt

#!/bin/bash
#########################
#File name:ping.sh
#Version:v1.0
#Email:admin@test.com
#Created time:2023-01-03 15:57:46
#Description:
#########################
read -p "please input you test network:" net

for i in {10..20}
do
#       echo $net.$i
        ping -c 4 $net.$i  &>/dev/null
        if [ $? -eq 0 ]
        then
                echo "$net.$i is up" >> /tmp/host_up.txt
        else [ $? -ne 0 ]
                echo "$net.$i is down" >> /tmp/host_down.txt
        fi
done

运行结果

[root@localhost homework4]# bash ping.sh
please input you test network:192.168.6
[root@localhost homework4]# cat /tmp/host_up.txt
192.168.6.20 is up
[root@localhost homework4]# cat /tmp/host_down.txt
192.168.6.10 is down
192.168.6.11 is down
192.168.6.12 is down
192.168.6.13 is down
192.168.6.14 is down
192.168.6.15 is down
192.168.6.16 is down
192.168.6.17 is down
192.168.6.18 is down
192.168.6.19 is down

3. 使用for实现批量主机root密码的修改

成功或失败都必须记录
提示：主机IP存放在一个文件中
SSH：实现公钥认证，执行远程中主机命令
实现公钥认证
#ssh-keygen 在用于管理的主上生成密钥对
#ssh-copy-id -i 192.168.2.3

ssh-keygen -f /root/.ssh/id_rsa -P '' -q $>/dev/null
for ip in `cat ipfile`
do
  echo $ip
  ssh-copy-copy-id root@$ip
done

for ip in `cat ipfile`
do
  echo $ip
  ssh root@ip "echo redhat | passwd --stdin root" &>/dev/null
  if [ "$?" -eq 0 ]
  then
    echo "host $ip success update passwd" >> /tmp/ssh_success.txt
  else
    echo "host $ip error update passwd" >> /tmp/ssh_error.txt
  fi
done