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sherpaurgen
sherpaurgen

Reputation: 3274

How to extract the mx records from dig query using sed, awk or both tools

here is the dig query result

$ dig gmail.com mx 

; <<>> DiG 9.9.5-3ubuntu0.14-Ubuntu <<>> gmail.com mx
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60118
;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;gmail.com.         IN  MX

;; ANSWER SECTION:
gmail.com.      1484    IN  MX  20 alt2.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  10 alt1.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  30 alt3.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  5 gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  40 alt4.gmail-smtp-in.l.google.com.

;; Query time: 1 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Fri May 26 14:20:53 NPT 2017
;; MSG SIZE  rcvd: 161

i want to extract the ;;ANSWER SECTION: part ..here its ;; ANSWER SECTION:

gmail.com.      1484    IN  MX  20 alt2.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  10 alt1.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  30 alt3.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  5 gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  40 alt4.gmail-smtp-in.l.google.com.

although the dig provided exact answer with just dig gmail.com mx +short im curious if theres way by using awk, sed or combining both

Upvotes: 2

Views: 386

Answers (3)

sherpaurgen
sherpaurgen

Reputation: 3274

# dig gmail.com mx | awk '/;; ANSWER SECTION:/{p=1}!$0{p=0}p' | grep -v ANSWER
gmail.com.      3599    IN  MX  10 alt1.gmail-smtp-in.l.google.com.
gmail.com.      3599    IN  MX  40 alt4.gmail-smtp-in.l.google.com.
gmail.com.      3599    IN  MX  30 alt3.gmail-smtp-in.l.google.com.
gmail.com.      3599    IN  MX  5 gmail-smtp-in.l.google.com.
gmail.com.      3599    IN  MX  20 alt2.gmail-smtp-in.l.google.com.

Upvotes: 0

SLePort
SLePort

Reputation: 15471

With sed:

dig gmail.com mx | sed '/;; ANSWER SECTION:/,/^$/!d;//d;'

Upvotes: 1

Inian
Inian

Reputation: 85895

Use an Awk statement as below,

dig gmail.com mx | awk '$0==";; ANSWER SECTION:"{f=1; next}!NF{f=0;}f'

to get the output as you need.

gmail.com.      1484    IN  MX  20 alt2.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  10 alt1.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  30 alt3.gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  5 gmail-smtp-in.l.google.com.
gmail.com.      1484    IN  MX  40 alt4.gmail-smtp-in.l.google.com.

The idea is to match the line containing your pattern ;; ANSWER SECTION: set a flag on its occurrence and reset it at the next occurring empty field.

Upvotes: 2

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