通过正则表达式排除除 ip 地址以外的所有内容

Question

sh ip cef | i 0.0.0.0.*Vlan9
0.0.0.0/0            192.168.18.200          Vlan9

我只想从中取出ip地址，即排除0.0.0.0/0和Vlan9

我通过expect试了一下，但是不知为何不行

(?!Vlan9|0)\d+.\d+.\d+.\d+

expect -exact "#"
send -- "sh ip cef | i 0.0.0.0.*Vlan9 \r"
expect -exact "#"
set dst $expect_out(buffer)
regexp {(?!Vlan9|0)\d+.\d+.\d+.\d+} $dst match ipdst
#expect -exact "#"
#send -- "clear ip arp $ipdst\r"
#expect -exact "#"
puts "router is dst ip $ipdst"

顺便说一句，expect -exact "#" - 根据调试判断，它在单独的行上输出每个字符并进行粘合？

日志

./ssh 192.168.18.200

/***  DATE is Wed Mar 17 12:42:57 MSK 2021 ***/

spawn ssh -o StrictHostKeyChecking=no test@192.168.18.200
parent: waiting for sync byte
parent: telling child to go ahead
parent: now unsynchronized from child
spawn: returns {28141}

expect: does "" (spawn_id exp6) match glob pattern "*assword:"? no
Password:
expect: does "\rPassword: " (spawn_id exp6) match glob pattern "*assword:"? yes
expect: set expect_out(0,string) "\rPassword:"
expect: set expect_out(spawn_id) "exp6"
expect: set expect_out(buffer) "\rPassword:"
send: sending "123456\r" to { exp6 }
send: sending "sh ip cef | i 0.0.0.0.*Vlan9 \r" to { exp6 }

expect: does " " (spawn_id exp6) match glob pattern "#"? no


expect: does " \r\n" (spawn_id exp6) match glob pattern "#"? no

Answer 1

请尝试：

regexp {(?!Vlan9|0)(\d+\.\d+\.\d+\.\d+)} $dst match ipdst

或：

regexp {(?!Vlan9|0)\d+\.\d+\.\d+\.\d+} $dst ipdst

您需要用括号将正则表达式括起来以捕获子匹配项。在上面的第二个语句中，ipdst 赋值给了整个匹配的子串，这也是有道理的。
你需要转义文字点，否则它会匹配任何字符。

[编辑]
如果您的 expect 版本不支持 lookaround assertions，请试试：

regexp {(\d+\.\d+\.\d+\.\d+)\s+Vlan9} $dst match ipdst

或万不得已：

regexp {([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)[^0-9]+Vlan9} $dst match ipdst

这将适用于非常旧的 expect 或 tcl。

[编辑]
这是 ssh 登录交易的示例：

#!/usr/bin/expect

set host "localhost"            ;# change to your server name
set user "guest"                ;# user name
set pass "secret123"            ;# password

spawn ssh $host -l $user
expect "assword:"
send "$pass\n"
expect "Last login:"
expect "$ "                    ;# command prompt (may differ depending on the system)
send "hostname\n"               ;# just an example; replace with your preferred command
expect "\n"                     ;# newline of the echo back of the sent command
expect "*\n"                    ;# wait for the server's response
set response $expect_out(0,string)
puts "server's response is $response"

通过正则表达式排除除 ip 地址以外的所有内容

exclude everything except ip address via regexp

regex

expect