Bash script iterate through file and delete block of text using sed - json

Question

I have a JSON file with the following contents:
[
{
"url" : "www.google.com",
"valid_from" : " Jul 31 10:16:13 2017 GMT",
"valid_till" : " Jul 31 10:16:13 2019 GMT",
"validity" : "Valid",
"days" : "464"
},
{
"url" : "www.youtube.com",
"valid_from" : " Apr 9 12:12:17 2017 GMT",
"valid_till" : " Apr 9 12:12:17 2019 GMT",
"validity" : "Valid",
"days" : "351"
}
]
I want to delete a block of JSON by passing a url argument corresponding to the block to delete.
I have a script cert-check-script-delete.sh which contains the following code:
line_num=1
cat certs.json >> certs-new.json
while read p; do # Iterate through each line in certs.json
if [[ $p == *"$1"* ]]; # Check if current line contains argument
then
sed -i "${line_num-1}d" certs-new.json # {
sed -i "${line_num}d" certs-new.json # Url
sed -i "${line_num+1}d" certs-new.json # Valid from
sed -i "${line_num+2}d" certs-new.json # Valid till
sed -i "${line_num+3}d" certs-new.json # Validity
sed -i "${line_num+4}d" certs-new.json # Days
sed -i "${line_num+5}d" certs-new.json # }
break
fi
((line_num++))
done <certs.json
mv certs-new.json certs.json
And after running my script with argument www.youtube.com I'm getting weird behaviour where it seems to just be deleting random lines:
{
"valid_from" : " Jul 31 10:16:13 2017 GMT",
"validity" : "Valid",
{
"valid_till" : " Apr 9 12:12:17 2019 GMT",
"validity" : "Valid",
"days" : "351"
}
]
I know I should use jq for inserting/deleting JSON but I'm not able to install it at work, so please don't just comment saying use jq.
Any help is appreciated!

Answer 1

You can do it like below:-
sed -i '/www.youtube.com/I,+6 d;$!N;/www.youtube.com/!P;D' certs-new.json
If your search string has been provided as command line parameter use like
sed -i '/'$1'/I,+6 d;$!N;/'$1'/!P;D' certs-new.json
How will it work, First it will search for pattern www.youtube.com and delete 6 lines below the pattern and second part of sed command will search for pattern www.youtube.com and delete the pattern line and one line above it.
In your example the output will be:-
[
{
"url" : "www.google.com",
"valid_from" : " Jul 31 10:16:13 2017 GMT",
"valid_till" : " Jul 31 10:16:13 2019 GMT",
"validity" : "Valid",
"days" : "464"
},
]