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 --- License: All the text on this website is free as in freedom unless stated otherwise. This means you can use it in any way you want, you can copy it, change it the way you like and republish it, as long as you release the (modified) content under the same license to give others the same freedoms you've got and place my name and a link to this site with the article as source. This site uses Google Analytics for statistics and Google Adwords for advertisements. You are tracked and Google knows everything about you. Use an adblocker like ublock-origin if you don't want it. All the code on this website is licensed under the GNU GPL v3 license unless already licensed under a license which does not allows this form of licensing or if another license is stated on that page / in that software: This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . Just to be clear, the information on this website is for meant for educational purposes and you use it at your own risk. I do not take responsibility if you screw something up. Use common sense, do not 'rm -rf /' as root for example. If you have any questions then do not hesitate to contact me. See https://raymii.org/s/static/About.html for details.