我想知道我的代码有什么问题吗？我想念什么？为什么该IF语句不能正常工作？为什么只显示一个输出？为什么该elif语句不起作用？我尝试托管3个服务器，即www.ee和www.eu以及www.com，然后再次托管它们，以确定它们是否具有IPv6地址或邮件服务器。
编辑：应该这样工作：
1）创建名为nimed.sh的脚本
2）在输入处，主机执行.ee；。欧洲联盟; .com主机。
3）如果主机不存在，请打印"Host not found"
4）主机地址将首先显示找到的相应电子邮件服务器地址。(Use commands sort, awk, tail or head)。必须删除主句末尾的点。像这样显示：？.com。（删除点=？.com）
5）如果找不到邮件服务器，则打印 "mail server not found"
6）如果找到了邮件服务器，请使用host命令询问邮件服务器的IP地址。
7）如果邮件服务器获得了IPv6地址，则打印"found IPv6"，如果没有，则打印"IPv6 not found"
那就是我需要做的，我被困在第7部分。这是一项通过练习来学习bash的学校练习。它是可选的，不是强制性的。
#!/bin/bash
m1="has address"
m2="has IPv6 address"
m3="mail is handled by 0 ."
m4="found IPv6"
m5="IPv6 not found"
m6="mail server not found"
###########################################################################################################################
host "$(host www.ee | sort | grep "mail is handled" | head -1 | awk '{print $7}')" >> www.all.txt
#first line shows this to www.all.txt
#aspmx.l.google.com has address 108.177.14.26
#aspmx.l.google.com has IPv6 address 2a00:1450:4010:c03::1b
host "$(host www.eu | sort | grep "mail is handled" | head -1 | awk '{print $7}')" >> www.all.txt
#second line shows this to www.all.txt
#mail.www.eu has address 46.105.44.68
host "$(host www.com | sort | grep "mail is handled" | head -1 | awk '{print $7}')" >> www.all.txt
#third line shows this to www.all.txt
#ASPMX.L.GOOGLE.com has address 108.177.14.26
#ASPMX.L.GOOGLE.com has IPv6 address 2a00:1450:4010:c03::1b
file="www.all.txt" #and this file has this in total:
#aspmx.l.google.com has address 108.177.14.26
#aspmx.l.google.com has IPv6 address 2a00:1450:4010:c03::1b
#mail.www.eu has address 46.105.44.68
#ASPMX.L.GOOGLE.com has address 108.177.14.26
#ASPMX.L.GOOGLE.com has IPv6 address 2a00:1450:4010:c03::1b
while read line #now this is where it gets messy. I don't know what to do-
#with line variable
do
if grep -q "$m2" $file #if string 'has IPv6 address' is in www.all.txt
then
awk 'NR==1 {print $1}' #go to line 1 and print the first text
# aspmx.l.google.com
echo "${m4}" #print 'Found IPv6'
elif grep -q "$m1" $file; then #else if string 'has address' is in
# www.all.txt then
awk 'NR==2 {print $1}' #go to line 2 and print the first text
echo "${m5}" #print 'IPv6 not found'
elif grep -q "$m3" $file; then #if string 'mail is handled by 0 .'
#is in www.all.txt then
echo "${m6}" #print 'mail server does not exist'
else #if none of the above was correct then
echo "${m6}" #mail server does not exist and
echo "${m5}" #IPv6 not found
fi #end the if-elif-else statement
done < $file #end the while loop
它创建的文件：
kristen@kristen-virtual-machine:~/Desktop$ ./nimed.sh
aspmx.l.google.com
found IPv6
kristen@kristen-virtual-machine:~/Desktop$ ls
koopia.sh nimed.sh TEST.sh www.all.txt
kristen@kristen-virtual-machine:~/Desktop$ cat www.all.txt
aspmx.l.google.com has address 64.233.161.26
aspmx.l.google.com has IPv6 address 2a00:1450:4010:c0e::1b
mail.www.eu has address 46.105.44.68
ASPMX.L.GOOGLE.com has address 64.233.161.26
ASPMX.L.GOOGLE.com has IPv6 address 2a00:1450:4010:c0e::1b
kristen@kristen-virtual-machine:~/Desktop$
测试1：成功
Correct program output
--- Input ---
www.ee
--- Program output ---
aspmx.l.google.com
found IPv6
--- Expected output (text)---
aspmx.l.google.com
found IPv6
测试2：失败
Incorrect program output
--- Input ---
www.eu
--- Program output ---
aspmx.l.google.com
Found IPv6
--- Expected output (text)---
mail.www.eu
Didn't find IPv6
有一阵子，我开始工作了。我犯了一个严重错误，没有正确阅读文字。好吧，当我发现需要使用read：D时，这是一项简单的锻炼。
这是我的问题的答案：
#!/bin/bash
m1="has address"
m2="has IPv6 address"
m3="mail is handled by 0 ."
m4="on IPv6"
m5="ei ole IPv6"
m6="mailiserverit pole"
m7="NXDOMAIN"
f="www.all.txt"
read -p "Sisesta host: " hostname
host $hostname | sort > $f
if grep -q "$m3" $f; then
echo "$m6"
echo "$m5"
elif grep -q "$m2" $f; then
awk 'NR==3 {print $7}' $f
echo "$m4"
elif host "$(host $hostname | sed 's/\.$//' | tail -1 | awk '{print $7}')" > www.all.txt && grep -q "mx-eu.mail.am0.yahoodns.net" $f; then
awk 'NR==1 {print $1}' $f
echo "$m5"
elif grep -q "$m7" $f; then
echo "hosti pole"
else
host "$(host $hostname | sed 's/\.$//' | sort | awk 'NR==2 {print $7}')" > $f
if grep -q "$m2" $f; then
awk 'NR==1 {print $1}' $f
echo "$m4"
elif grep -q "$m1" $f; then
awk 'NR==1 {print $1}' $f
echo "$m5"
fi
fi
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我来说两句