Linux cloud computing architecture-shell entry to proficient (give up)[3]
1. Expect to achieve no interactive login
# 安装expect
[root@client ~]# yum install expect -y
[root@client ~]# which expect
/usr/bin/expect
# 定义脚本执行的shell,即expect可执行文件的链接路径
#!/usr/bin/expect
# 设置超时时间
set timeout 30
set timeout -1
# 设置变量
set name "abong"
set passwd "123456"
# spawn命令，功能是给ssh进程加个壳，用来传递交互指令。【交互式输入的首条命令】
# expect命令，判断输出结果是否包含字符串，没有则立即返回。有则等待timeout时间后再返回。【交互式输入】
# send命令，执行交互动作。
# exp_continue命令，继续执行交互动作。
# interact命令，执行完交互动作后，把控制权交给控制台，若无该命令，交互完直接退出。
# $argv：expect脚本可以接受bash传递过来的参数，可以使用[lindex $argv n]获得，n从0开始。
# 交互式输入账号密码使用ssh登录远程主机
# 默认timeout为10s
[root@client ~]# vim ssh.exp
#!/usr/bin/expect
set ipaddr "192.168.10.10"
set name "root"
set passwd "123456"
set timeout 30
spawn ssh $name@$ipaddr
expect {
"yes/no" {
send "yes\r";exp_continue}
"password" {
send "$passwd\r"}
}
expect {
"#"}
send "touch /root/a.txt\r"
send "ls /etc > /root/a.txt\r"
send "exit\r"
expect eof
[root@client ~]# chmod +x ssh.exp
[root@client ~]# expect ssh.exp
spawn ssh [email protected]
[email protected]'s password:
Last login: Sun Aug 2 20:32:30 2020 from 192.168.10.43
[root@master-lvs ~]# touch /root/a.txt
[root@master-lvs ~]# ls /etc > /root/a.txt
[root@master-lvs ~]# exit
登出
Connection to 192.168.10.10 closed.
# 免密使用ssh登录多台远程主机进行操作
[root@client ~]# vim ipaddr.txt
192.168.10.10 123456
192.168.10.20 123456
[root@client ~]# vim ssh.exp
#!/usr/bin/expect
set ipaddr [lindex $argv 0]
set name "root"
set passwd [lindex $argv 1]
set timeout 30
spawn ssh $name@$ipaddr
expect {
"yes/no" {
send "yes\r";exp_continue}
"password" {
send "$passwd\r"}
}
expect {
"#"}
send "touch /root/a.txt\r"
send "ls /etc > /root/a.txt\r"
send "exit\r"
expect eof
[root@client ~]# chmod +x ssh.exp
[root@client ~]# vim login.sh
#!/bin/bash
for ip in `awk '{print $1}' /root/ipaddr.txt`
do
pass=`grep $ip /root/ipaddr.txt | awk '{print $2}'`
expect /root/ssh.exp $ip $pass
done
[root@client ~]# chmod +x login.sh
# 执行登录脚本
[root@client ~]# bash login.sh
spawn ssh [email protected]
[email protected]'s password:
Last login: Sun Aug 2 21:08:42 2020 from 192.168.10.43
[root@master-lvs ~]# touch /root/a.txt
[root@master-lvs ~]# ls /etc > /root/a.txt
[root@master-lvs ~]# exit
登出
Connection to 192.168.10.10 closed.
spawn ssh [email protected]
[email protected]'s password:
Last login: Sun Aug 2 21:09:23 2020 from 192.168.10.43
[root@backup_lvs ~]# touch /root/a.txt
[root@backup_lvs ~]# ls /etc > /root/a.txt
[root@backup_lvs ~]# exit
登出
Connection to 192.168.10.20 closed.
2. Shell regular expressions
Basic regular expression
| Special characters | description |
|---|---|
| ^ | Match beginning |
| $ | End of match |
| * | Match the previous character 0 or more times, match * with \* |
| + | Match the previous character one or more times, match * with \+ |
| ? | Match the previous character 0 or 1 times, match * with \? |
| \ | Escapes |
| . | Match all single characters except newline \n |
| () | Match the start position and end position of parenthesis expression, match (use \(, match) use \) |
| [] | Match the start and end positions of the square bracket expression, match [with \[, match] with \] |
| {} | Match the start position and end position of the brace expression, match {with \{, match} with \} |
| | | Or, match|use\ |
| \n | Match newline |
| \r | Match carriage return |
| \t | Match tab |
# 去除/etc/ssh/sshd_config文件中的空行和#号开头的行
# 使用基础正则表达式
[root@client ~]# cat /etc/ssh/ssh_config | grep -v "^$" | grep -v "^#"
[root@client ~]# cat /etc/ssh/ssh_config | grep -v "^$\|^#"
# 使用扩展正则表达式
[root@client ~]# cat /etc/ssh/ssh_config | grep -E -v "^$|^#"
[root@client ~]# cat /etc/ssh/ssh_config | egrep -v "^$|^#"
# 匹配.字符,除换行符\n外的所有单个字符
[root@client ~]# grep .ot /etc/passwd
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
setroubleshoot:x:991:985::/var/lib/setroubleshoot:/sbin/nologin
3. bash check script and view script execution process
3.1 bash checks the script for syntax errors
bash -v script_name.sh Check if there is a syntax error in bash
[root@client ~]# cat ping.sh
#!/bin/bash
for ((i=40;i<45;i++))
do
ping -c 3 192.168.10.$i &> /dev/null
if [ $? -ne 0 ] ; then
echo "192.168.10.$i is shutdown"
else
echo "192.168.10.$i is startup"
fi
done
[root@client ~]# bash -v ping.sh
#!/bin/bash
for ((i=40;i<45;i++))
do
ping -c 3 192.168.10.$i &> /dev/null
if [ $? -ne 0 ] ; then
echo "192.168.10.$i is shutdown"
else
echo "192.168.10.$i is startup"
fi
done
192.168.10.40 is shutdown
192.168.10.41 is shutdown
192.168.10.42 is shutdown
192.168.10.43 is startup
192.168.10.44 is shutdown
3.2 bash view the detailed execution process of the script
bash -x script_name.sh View the detailed execution process of bash
[root@client ~]# cat ping.sh
#!/bin/bash
for ((i=40;i<45;i++))
do
ping -c 3 192.168.10.$i &> /dev/null
if [ $? -ne 0 ] ; then
echo "192.168.10.$i is shutdown"
else
echo "192.168.10.$i is startup"
fi
done
[root@client ~]# bash -x ping.sh
+ (( i=40 ))
+ (( i<45 ))
+ ping -c 3 192.168.10.40
+ '[' 1 -ne 0 ']'
+ echo '192.168.10.40 is shutdown'
192.168.10.40 is shutdown
+ (( i++ ))
+ (( i<45 ))
+ ping -c 3 192.168.10.41
+ '[' 1 -ne 0 ']'
+ echo '192.168.10.41 is shutdown'
192.168.10.41 is shutdown
+ (( i++ ))
+ (( i<45 ))
+ ping -c 3 192.168.10.42
+ '[' 1 -ne 0 ']'
+ echo '192.168.10.42 is shutdown'
192.168.10.42 is shutdown
+ (( i++ ))
+ (( i<45 ))
+ ping -c 3 192.168.10.43
+ '[' 0 -ne 0 ']'
+ echo '192.168.10.43 is startup'
192.168.10.43 is startup
+ (( i++ ))
+ (( i<45 ))
+ ping -c 3 192.168.10.44
+ '[' 1 -ne 0 ']'
+ echo '192.168.10.44 is shutdown'
192.168.10.44 is shutdown
+ (( i++ ))
+ (( i<45 ))