Extract string from a given file using awk.

Question

I have a file named.conf, here first i need to find himanshu.com and then extract the corresponding zone file i.e. for1 , I don't know what parameters would be passed to the awk script to find pattern two lines below.

named.conf

options {


directory "/var/named";

};



zone "himanshu.com" in {
type master;
file "for1";
};

zone "0.168.192.in-addr.arpa" in {
type master;
file "rev";
};

@Gaius -A2 shows 2 lines below/after matching, not the 2nd line below matching. — Kent
– Kent, Commented Jun 5, 2014 at 14:00
Plus, the file line might not be exactly 2 below the zone line. If this were true, you could do grep -A2 himanshu.com named.conf | grep file | cut -d\" -f2 — S. Ahn
– S. Ahn, Commented Jun 5, 2014 at 15:41

dogbane · Accepted Answer · 2014-06-05 14:18:59Z

1

Using awk:

$ awk '/himanshu.com/ {found=1} /^file/ && found {print $0; exit}' file
file "for1";

This command sets a flag called found when it sees himanshu.com and then prints out the file if the flag has been set.

Another way using sed:

$ sed  -n '/himanshu/,/}/{/^file/s/.*\"\(.*\)\".*$/\1/p}' file
for1

This command first gets all lines between himanshu and the next } (inclusive), then searches for file within that block and finally uses a regex to extract the name of the file.

edited Jun 5, 2014 at 14:18

answered Jun 5, 2014 at 14:06

dogbane

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2 Comments

Kent Over a year ago

this is a clever solution. it should work for OP's requirement. there is one exception, if in himanshu block, no file occurs, the awk and sed line may output the wrong file name. As I said, it may not be the case that OP should take care about.

dogbane Over a year ago

that's easily fixed in the sed commmand, using sed -n '/himanshu/,/}/ to grab the whole block. (answer updated)

Kent · Accepted Answer · 2014-06-05 13:57:44Z

1

$ awk -v RS="" -F'\n' '/zone "himanshu.com"/{for(i=1;i<=NF;i++)if($i~/^file /)print $i}' file
file "for1";

the above line will first focus on the zone "himanshu.com" block, then extract the file ... line. no matter it locates how many line after the zone "hi..." line.

answered Jun 5, 2014 at 13:57

Kent

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1 Comment

Kent Over a year ago

I would add that if your zone "him..." block contained empty lines, the solution will fail.

Avinash Raj · Accepted Answer · 2014-06-05 13:53:34Z

0

Try this awk command,

$ awk '/zone "himanshu.com"/ {getline; getline; print;}' file
file "for1";

OR

Run the below command to get the exact file name,

$ awk '/zone "himanshu.com"/ {getline; getline; print $2}' file
"for1";

$ awk '/zone "himanshu.com"/ {getline; getline; gsub (/";/,"",$2); gsub (/^"/,"",$2); print $2}' file
for1

answered Jun 5, 2014 at 13:53

Avinash Raj

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Comments

Scrutinizer · Accepted Answer · 2014-06-05 14:49:14Z

0

awk variation:

awk -F\" '$1~/zone/ && $2==s, /}/ {if($1~/file/) print $2}' s=himanshu.com file

answered Jun 5, 2014 at 14:49

Scrutinizer

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