This is a text-only version of the following page on https://raymii.org:
---
Title       : 	Get a JSON value with bash and sed
Author      : 	Remy van Elst
Date        : 	26-02-2019
URL         : 	https://raymii.org/s/snippets/Get_json_value_with_sed.html
Format      : 	Markdown/HTML
---



Recently I was asked to get one value from a json object using only shell tools.
The json in question is from a [dutch radio station][1] and it lists the current
song that is played. Using this together with a few shell commands and `notify-
send` we can show the current song when it changes as a desktop notification.
I'd rather use Python or `jq` if it has to be shell. In this case the co-worker
asked to just use simple shell tools and no external dependencies.

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This is the `json` file, formatted:

    
    
    # curl -s 'https://api.grootnieuwsradio.nl/playing.json'
    {
        "Stream_information":{
            "Name":"grootnieuws_ipad",
            "NameByClient":"grootnieuwsradio_website_aac",
            "Limit":"2000",
            "Account":"calculation",
            "IncomingSignal":"offline",
            "SecureTokenSharedSecret":"",
            "SecureTokenQueryParametersPrefix":"",
            "SecureTokenIncludeClientIPInHash":"false",
            "MultiBitrateEnable":"false",
            "DVREnable":"false",
            "PlayIPWhiteList":"",
            "PublishIPWhitelist":"",
            "SimultaneousConnections":"1729",
            "Auto_recording":"off",
            "PlayingNow":"Joke Buis - Welk Een Vriend Is Onze Jezus",
            "Encoder_visitors_statistics":{
                "REST_URI":"https:\/\/api.streampartner.nl\/grootnieuws_ipad\/stream_information\/encoder_visitors_statistics",
                "Options":[
                    "GET"
                ]
            }
        }
    }
    

The field we want is the `PlayingNow` field. Using `sed`, a regular expression
with a backreference (`\1`) it can be shown:

    
    
    sed -n 's|.*"PlayingNow":"\([^"]*\)".*|\1|p'
    

Example output:

    
    
    curl -s 'https://api.grootnieuwsradio.nl/playing.json' | sed -n 's|.*"PlayingNow":"\([^"]*\)".*|\1|p'
    
    Joke Buis - Welk Een Vriend Is Onze Jezus
    

The full script to send the desktop notifications:

    
    
    #!/bin/bash
    PATH="/usr/local/bin:/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin:/usr/local/sbin:$PATH"
    if [[ ! -f /tmp/gnr-prev.txt ]]; then touch /tmp/gnr-prev.txt; fi
    PREVSONG="$(cat /tmp/gnr-prev.txt)"
    curl -s 'https://api.grootnieuwsradio.nl/playing.json' | sed -n 's|.*"PlayingNow":"\([^"]*\)".*|\1|p' > /tmp/gnr-cur.txt
    CURSONG="$(cat /tmp/gnr-cur.txt)"
    if [[ "$PREVSONG" != "$CURSONG" ]]; then
        mv /tmp/gnr-prev.txt /tmp/gnr.$(date +%s).txt;
        mv /tmp/gnr-cur.txt /tmp/gnr-prev.txt;
        notify-send "GNR: $CURSONG";
    fi
    

Put it in `cron` for regular execution. Add this to your crontab as well if you
use KDE:

    
    
    DISPLAY=:0.0
    XAUTHORITY=/home/remy/.Xauthority
    

Replace `remy` with your username.

   [1]: https://www.grootnieuwsradio.nl/
   [2]: https://www.digitalocean.com/?refcode=7435ae6b8212

---

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