Cat command with sed - json

Question

I have a file:
{
"test_data": [
{
"id": "1",
"pm": "30",
"mp": "40"
}
],
"test": [
"id",
"pm",
"mp"
]
}
I want to extract test_data. Output:
"test_data": [
{
"id": "1",
"pm": "30",
"mp": "40"
}
],
I try this command: cat myFile | sed -n '/^"test_data": \[$/,/^\],$/p'
But it's don't work. An idea ?
Thanks you !

Answer 1

jq seems the right tool for the job :
$ jq '.|{test_data:.test_data}' filename
{
"test_data": [
{
"id": "1",
"pm": "30",
"mp": "40"
}
]
}

Answer 2

Solution 1st: With sed
sed -n '/"test_data"/,/],/p' Input_file
OR: as per OP, OP needs to append a string/data after a line matches:
sed -n '/"test_data"/,/],/p;/],/s/$/"test"/p' Input_file
OR2: If one wants to add an another file's content to a match then following may help in same:
sed -n '/"test_data"/,/],/p;/],/r another_file' Input_file
Solution 2nd: Following simple awk may help you in same.
awk '/test_data/, /],/' Input_file
Output will be as follows.
"test_data": [
{
"id": "1",
"pm": "30",
"mp": "40"
}
],
Logic for above solutions:
For sed: -n option in sed will turn OFF the printing of any line till it is explicitly mentioned to print it, then by doing /"test_data"/,/],/ I am letting sed know that I need to get the data from test_data to till ,/] and mentioning p after that will make sure those lines which are coming in this range are getting printed here/
For awk: Simply mentioning the range from /"test_data"/,/],/ and not mentioning any action so when any line comes into this range condition becomes true and since no action mentioned so by default print of that line happens then.

Answer 3

You can try that with gnu
csplit -s -z infile %test_data%-1 /],/1;rm xx01;echo "Add Text here" >> xx00;cat xx00

Answer 4

The right way is jq tool:
jq 'del(.test)' inputfile
The output:
{
"test_data": [
{
"id": "1",
"pm": "30",
"mp": "40"
}
]
}