How to define a variable in a BASH script by using a JSON file online? Post: 302869177

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Top Forums Shell Programming and Scripting How to define a variable in a BASH script by using a JSON file online? Post 302869177 by nbsparks on Tuesday 29th of October 2013 05:47:52 PM

10-29-2013

Registered User

How to define a variable in a BASH script by using a JSON file online?

Hello,

I would like to modify an existing script of mine that uses a manually defined "MCVERSION" variable and make it define that variable instead based on this JSON file stored online:
https://s3.amazonaws.com/Minecraft.D.../versions.json

Within that JSON, I 'm looking for this information:

Code:

{
  "latest": {
    "snapshot": "1.7.2",
    "release": "1.7.2"
  },

I want $MCVERSION to equal the "latest/release" value above (in this case, MCVERSION=1.7.2). I'm perfectly OK with pulling the JSON file down locally first via "wget" command. In fact, I'd prefer that so I can reference it if needed if my script fails (in case they change their JSON file format).

Here is my script (not that it matters too much for this example, I doubt).

Code:

#!/bin/bash

#### Define the current version of Minecraft
MCVERSION=1.7.2

#### Remove any current versions and create new folder for the JAR file
cd /home/mcmaps/.minecraft/versions
rm * -rf
mkdir $MCVERSION
cd /home/mcmaps/.minecraft/versions/$MCVERSION/

#### Download fresh copy of Minecraft JAR file for use of textures
wget https://s3.amazonaws.com/Minecraft.Download/versions/$MCVERSION/$MCVERSION.jar -P ~/.minecraft/versions/$MCVERSION/

Currently, the script results in creating this file:
/home/mcmaps/.minecraft/versions/1.7.2/1.7.2.jar

The goal is to do that without ever having to manually modify the MCVERSION variable in this script.

nbsparks

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LEARN ABOUT DEBIAN

jigdo-mirror

JIGDO-MIRROR(1) 														   JIGDO-MIRROR(1)

NAME

       jigdo-mirror - Maintain a mirror of images offered with jigdo

SYNOPSIS

       jigdo-mirror [ config-file ]

DESCRIPTION

       See jigdo-file(1) for an introduction to Jigsaw Download.

       jigdo-mirror  is a script intended for people who want to offer direct HTTP or FTP downloads of files for which only the jigdo and template
       files are available.

       As the first step of using jigdo-mirror, you need to set up normal HTTP/FTP/rsync mirroring both of the `.jigdo'/`.template' files  and	of
       the  parts  that  are  needed  for the reconstruction of the images. For example, in the case that you want to mirror Debian CD images with
       jigdo-mirror, you need a mirror of the `.jigdo'/`.template' files and a Debian mirror on the local machine.

       At regular intervals (preferably immediately after the normal mirroring has finished), schedule a  run  of  jigdo-mirror.  It  will  search
       through a given directory for any `.jigdo' files and attempt to create all images offered by each file.

       The  script  requires  you  to  set a number of variables - please refer to the start of /usr/bin/jigdo-mirror for a description of each of
       them. Since /usr/bin/jigdo-mirror will be overwritten whenever you upgrade jigdo-mirror, it is highly recommended not to  change  the  set-
       tings  directly	in  this script. Instead, personal settings should be saved in a file called .jigdo-mirror in your home directory, or in a
       different file whose name is then passed to the script as its first (and only) command line argument.

SEE ALSO

       jigdo-file(1), jigdo-lite(1)

       CD images for Debian Linux can be downloaded with jigdo <URL:http://www.debian.org/CD/jigdo-cd/>.

AUTHOR

       Jigsaw Download <URL:http://atterer.net/jigdo/> was written by Richard Atterer <jigdo atterer.net>, to make downloading of  CD  ROM  images
       for the Debian Linux distribution more convenient.

								    19 May 2006 						   JIGDO-MIRROR(1)