CODEWITHSUNDEEP
jsonregexlinuxbash
heaphach
heaphach

Reputation: 1492

Linux bash parse json: Get first & last date

I have a JSON variable from curl like the below (@stackoverflow=pretty printed) and I want to get two pieces of information. The date which is the first calendar date and the last calendar date (ISO 8601), but I have no idea how to do this in bash. On top I have to calculate the duration between these two dates (could be just some milliseconds or much more).

Anyone any idea how I can solve my problem?

{
    "results": [{
        "...": "...",
        "date": "2012-09-15T14:04:00.741+0200",
        "...": "..."
    },
    {
        "...": "...",
        "date": "2015-09-15T14:04:00.741+0200",
        "...": "..."
    },
    {
        "...": "...",
        "date": "2015-09-11T14:04:00.741+0200",
        "...": "..."
    },
    {
        "...": "...",
        "date": "2015-09-15T14:04:00.741+0200",
        "...": "..."
    },
    {
        "...": "...",
        "date": "2015-09-15T14:04:30.741+0200",
        "...": "..."
    },
    {
        "...": "...",
        "date": "2019-09-15T14:04:00.741+0200",
        "...": "..."
    },
    {
        "...": "...",
        "date": "1015-09-15T14:04:00.741+0200",
        "...": "..."
    }]
}

For your information: Its a test script I have to use, because there is some more magic in it I don't want to rewrite in other script languages.

Upvotes: 0

Views: 400

Answers (3)

heaphach
heaphach

Reputation: 1492

Here is what works for me:

   echo $JSON | tr '"' '\n' | sed -n '/date/{n;n;p}'
   dates=$(echo $JSON | tr '"' '\n' | sed -n '/date/{n;n;p}')
   for date in ${dates[@]}
      do
      echo $date
   done

Upvotes: 0

chepner
chepner

Reputation: 532053

Use jq to parse the JSON and extract all the dates, then sort them and output the first and last dates.

curl ... | jq '.results[] | .date' | sort | awk 'NR==1; END {print}'

Upvotes: 2

William Pursell
William Pursell

Reputation: 212514

It's not clear exactly what the setting is, but if you have text in a variable names JSON, you can extract the lines containing the desired dates with:

echo "$JSON" | awk '/date/ && !a++; /date/ {l=$0} END {print l}'

(Depending on the deleted content; you might get some false hits and need a more tightly constrained regex). But parsing json with shell tools is really a bad idea.

Upvotes: 1

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