extract specific key value from json in bash if key matches

Question

I have a json content (output.json)

{"project": {"id": "A", "content": [{"name": "XYZ", "location": "Berlin", "comments":""}, {"name": "ABC", "location": "NewYork", "comments": "Hwllo"}, {"name": "DEF", "location": "Paris", "comments": "Success"}]}}

I would like to extract location key with value when name matches say ABC from the above json using bash or shell commands

I tried something like below which gives be content within curly braces. but not sure on searching specific key.

cat output.json | grep -o -e "{.*}"

Output expectations: if name matches ABC, get output as "location":"NewYork"

Any suggestions on processing further?

For extracting from json you should use jq if you can. According to authors "jq is like sed for JSON data". — Szczerba
– Szczerba, Commented Jan 18, 2019 at 13:20

Szczerba · Accepted Answer · 2019-01-18 13:39:12Z

4

For extracting from json you should use jq if you can. According to authors "jq is like sed for JSON data" (source).

In your case it should be:

$ jq -r '.project' output.json | jq -r '.content' | jq '.[] | select(.name=="ABC")' | jq -r '.location'

Output will be:

NewYork

To get output which you required so:

"location":"NewYork"

You can use:

echo "\"location\":$(jq -r '.project' output.json | jq -r '.content' | jq '.[] | select(.name=="ABC")' | jq '.location')"

Before you use jq you should install it on Debian and Ubuntu it will be:

$ sudo apt install jq

for other OS you should check this site.

edited Jan 18, 2019 at 13:39

answered Jan 18, 2019 at 13:24

Szczerba

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1 Comment

stackover flow Over a year ago

Thank you. Looks interesting, gonna try now :)

Jithin Scaria · Accepted Answer · 2019-01-18 13:17:23Z

1

There may be better ways to do it, in a quick twisted way is here.

cat output.json | sed 's/"name"/\n"name"/g' | grep '"name"' | awk -F',' '{print $2}'

Add | grep <preferred name> also if need to filter based on name.

answered Jan 18, 2019 at 13:17

Jithin Scaria

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4 Comments

stackover flow Over a year ago

Thank you. This is good. but unfortunately, key location is not always in second place. awk with $2 is like hardcoded.

Jithin Scaria Over a year ago

ohh .. ok then we can add one more sed before that, like cat output.json | sed 's/"name"/\n"name"/g' | grep '"name"' | sed 's/"location"/\n"location"/g' | awk -F',' '{print $1}' ... ;)

stackover flow Over a year ago

When I do this... I get both name and location key value pair. I still need to use tail -1 at the end which doesnt look good when the order is different

Jithin Scaria Over a year ago

Yea its true ... ;)

stack0114106 · Accepted Answer · 2019-01-18 13:45:17Z

0

Use Perl

$ perl -0777 -lne ' while(/"name":\s+"ABC",\s+"location":\s+(\S+)/msg) { print "$1\n" } ' output.json
"NewYork",
$ cat output.json
{"project": {"id": "A", "content": [{"name": "XYZ", "location": "Berlin", "comments":""}, {"name": "ABC", "location": "NewYork", "comments": "Hwllo"}, {"name": "DEF", "location": "Paris", "comments": "Success"}]}}
$

answered Jan 18, 2019 at 13:45

stack0114106

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1 Comment

stack0114106 Over a year ago

glad to hear that!.. please consider accepting the answer

Reino · Accepted Answer · 2025-03-07 16:28:31Z

Tools like grep (using RegEx) don't understand JSON. Please use a dedicated parser like xidel instead:

$ xidel -s output.json \
  -e '$json/project/(content)()[name="ABC"]/location'        # XPath-like notation
  -e '$json/(.//content)()[name="ABC"]/location'
  -e '($json//content)()[name="ABC"]/location'
  -e '($json).project.content()[name="ABC"].location'               # dot notation
  -e '($json)("project")("content")()[name="ABC"]("location")'   # JSONiq notation
  -e '$json?project?content?*[name="ABC"]?location'             # XPath 3.1 syntax

If you literally require the output to be "location":"NewYork":

$ xidel -s output.json \
  -e '($json//content)()[name="ABC"]/concat("""location"":""",location,"""")'
  -e '($json//content)()[name="ABC"]/("""location"":"""||location||"""")'
  -e '($json//content)()[name="ABC"]/`"location":"{location}"`'

The last variant, with the string between backticks (`...`) is an XPath 4.0 String Template where everything between curly brackets ({...}) is evaluated.

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