getting the desirable output with gawk/awk

Question

I run the following command:

aws ec2 describe-instances --filters "Name=ip-address,Values=MY_IP" | grep InstanceId 

and I get:

"InstanceId": "i-b0f13081",

How can I only get the following:

i-b0f13081

This is what I tried:

 aws ec2 describe-instances --filters "Name=ip-address,Values=MY_IP" | grep InstanceId | gawk -F: '{ print $2 }' 
 "i-b0f13081", 

Answer 1

awk:

Set " as field delimiter, and get the 4th field:

% awk -F'"' '{print $4}' <<<'"InstanceId": "i-b0f13081",'
i-b0f13081

---

Similarly cut:

% cut -d'"' -f4 <<<'"InstanceId": "i-b0f13081",'
i-b0f13081

---

grep with PCRE (-P):

% grep -Po ':\s*"\K[^"]+' <<<'"InstanceId": "i-b0f13081",'
i-b0f13081

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Shell parameter expansion:

% var='"InstanceId": "i-b0f13081",'
% var="${var%\"*}"
% echo "${var##*\"}"
i-b0f13081

---

sed:

% sed -E 's/^[^:]+:[^"]+"([^"]+).*/\1/' <<<'"InstanceId": "i-b0f13081",'
i-b0f13081

---

perl:

% perl -pe 's/^[^:]+:[^"]+"([^"]+).*/$1/' <<<'"InstanceId": "i-b0f13081",'
i-b0f13081

---

python:

% python -c 'import sys; print sys.stdin.read().split("\"")[3]' <<<'"InstanceId": "i-b0f13081",'
i-b0f13081