UNIX for Dummies Questions & Answers

#I'm quite new to scripting and my boss has asked me to solve a simple problem and sadly, I can't figure out how to do it. Any help is appreciated.


#The following is a small shell script and the output that it produces for google.com.

#!/bin/sh
whois $1 | grep "Name Server"
dig +short $1 mx
dig +short mail.$1

[jjamd64@localhost ~]$ ./dn.sh google.com
Name Server: NS1.GOOGLE.COM
Name Server: NS2.GOOGLE.COM
Name Server: NS3.GOOGLE.COM
Name Server: NS4.GOOGLE.COM
10 smtp3.google.com.
10 smtp4.google.com.
10 smtp1.google.com.
10 smtp2.google.com.
googlemail.l.google.com.
66.249.83.83
66.249.83.19

#I need to modify this script so that it deletes the spaces in the beginning of the "name server" line, deletes the numbers and space before the mx records and replaces with a + symbol, and places a - symbol before the IP's. Here is what it should look like:

[jjamd64@localhost ~]$ ./dn.sh google.com
Name Server: NS1.GOOGLE.COM
Name Server: NS2.GOOGLE.COM
Name Server: NS3.GOOGLE.COM
Name Server: NS4.GOOGLE.COM
+smtp3.google.com.
+smtp4.google.com.
+smtp1.google.com.
+smtp2.google.com.
googlemail.l.google.com.
-66.249.83.83
-66.249.83.19

#I would like to use the sed command if possible and any hints would be much appreciated. I'm open to other suggestions as long as it produces the desired output. I really appreciate any direction and tips. THANKS!

Out of interest, given that you say you can't figure it out, why do you care whether sed is used or not?

I would like to get more familiar with sed if possible, but I am open to absolutely any suggestions.

OK, I have the first two parts done, the following sed arguments produce the output I need, but I dont know how to insert the - symbol before the IP's. Anyone got any ideas?


#!/bin/sh
whois $1 | grep "Name Server"|sed "s/ //"
dig +short $1 mx|sed "s/[0-9][0-9] /+/"
dig +short mail.$1

[jjamd64@localhost ~]$ ./dn.sh google.com
Name Server: NS1.GOOGLE.COM
Name Server: NS2.GOOGLE.COM
Name Server: NS3.GOOGLE.COM
Name Server: NS4.GOOGLE.COM
+smtp3.google.com.
+smtp4.google.com.
+smtp1.google.com.
+smtp2.google.com.
googlemail.l.google.com.
66.249.83.83
66.249.83.19

Personally I would pipe it through a read loop

Code:

while read N
do
       case "$N" in
       [0-9]* )
             echo \-"$N"
             ;;
       * )
             echo "$N"
            ;;
       esac
done

But I'm sure some AWK guru can produce some hieroglyphics in a single line to do the job.

Try this:

Code:

sed 's/^\(..\....\...\...$\)/-\1/'

Regards