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Accepted
Cruise5
Asked: 2022-04-27 20:28:26 +0800 CST

无法在 shell 脚本中正确地从 IP 地址中提取八位字节

  • 772

ipfile.txt格式如下：

ServerA 127.0.0.1
ServerB 192.168.1.254
ServerC 4.2.2.1

shell脚本的期望输出：

ServerA   Class A
ServerB   Class C
ServerC   Class A

我想不出更好的方法来只提取第一个八位字节。到目前为止，我的脚本是：

#!/bin/bash

# Take input IP from file and classify according to classful addressing. 

while read ip;do
        octet=$(awk -F'[ .]' '{print $2}' ipfile.txt)
        if [[ "$octet" -ge 1 && "$octet" -le 127 ]];then
                echo "ServerA Class A"
        fi
        if [[ "$octet" -ge 128 && "$octet" -le 191 ]];then
                echo "ServerB Class B"
        fi
        if [[ "$octet" -ge 192 && "$octet" -le 223 ]];then
                echo "ServerC Class C"
        fi
done < ipfile.txt

我收到语法错误：

./ipclassgen.sh: line 7: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 10: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 13: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 7: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 10: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 13: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 7: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 10: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 13: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 7: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 10: [[: 127
192
4: syntax error in expression (error token is "192
4")
./ipclassgen.sh: line 13: [[: 127
192
4: syntax error in expression (error token is "192
4")

如何在不使用 awk 和指定文件的情况下做到这一点。我也不确定语法错误在哪里。

shell-script

1 个回答

  1. Best Answer

    您将文件逐行读取到ip变量中，但从不使用它。然后将所有行的第二个字段分配给octet变量，由<NL>(\n, 0x0A) 分隔，再次读取文件。然后在进行测试时bash偶然发现了多行。octet改为尝试：

    while read server ip
  do    octet=${ip%%.*}
.
.
.
  done < file

    另请注意，不硬编码服务器名称而是使用server从文件中读取的变量可能更聪明：

    if [[ "$octet" -ge 1 && "$octet" -le 127 ]]
  then  echo "$server: Class A"
  fi

    PS：您甚至可以read为您拆分线路：

    while IFS=" ." read server ip1 ip2 ip3 ip4
  do if [[ "$ip1" ...
    • 2

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