Added dev tool to simplify adding mods to the pack

Simply run ./mrpacktool [file url]

mrpacktool.sh

@@ -0,0 +1,64 @@
+#!/bin/bash
+
+# User input error handling
+if [[ $# -eq 0 ]]; then
+    echo "$0: A mod url is required."
+    exit 4
+fi
+
+# Do everything relative to this files path
+parent_path=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
+cd "$parent_path"
+
+# Paths
+mods_dir="/tmp/"
+
+# Options parsing
+mod_url="$1"
+out_file="${2:-$parent_path/modrinth.index.json}"
+
+if [ -n "$v" ]; then
+    echo "Verbose: $v, Mod url: $mod_url, Output: $out_file"
+fi
+
+# https://stackoverflow.com/questions/6250698/how-to-decode-url-encoded-string-in-shell#37840948
+function urldecode() {
+	: "${*//+/ }"
+	echo -e "${_//%/\\x}"
+}
+
+# Get file name from url trimmed by slash and url decoded
+mod_file="$(urldecode ${mod_url##*/})"
+trap "rm ${mods_dir}/${mod_file}" HUP INT TERM EXIT
+echo "Downloading file..."
+wget -N --no-verbose --directory-prefix "$mods_dir" "$mod_url"
+
+# Collect data required by modrinth.index.json
+echo "Processing file info"
+mod_path="${mods_dir}/${mod_file}"
+
+modrinth_size="$(du --bytes "$mod_path" | cut -f -1)"
+modrinth_sha1="$(sha1sum "$mod_path" | cut -d " " -f 1)"
+modrinth_sha512="$(sha512sum "$mod_path" | cut -d " " -f -1)"
+
+# Writing to file
+echo "Writing to file"
+jq ".files += [{ \
+  \"downloads\": [
+    \"${mod_url}\"
+  ],
+  \"env\": {
+    \"client\": \"required\",
+    \"server\": \"required\"
+  },
+  \"fileSize\": ${modrinth_size},
+  \"hashes\": {
+    \"sha1\": \"${modrinth_sha1}\",
+    \"sha512\": \"${modrinth_sha512}\"
+  },
+  \"path\": \"mods/${mod_file}\"
+}]" "$out_file" > "$out_file.tmp"
+
+mv "$out_file.tmp" "$out_file"
+
+[ $? -eq 0 ] && echo "Successfully appended mod to ${out_file}"