I was doing the client_id bit completely wrong. This should be much better.

ratatoskr.sh

@@ -17,28 +17,24 @@ get_oauth_token() {
             break
         fi
     done
-    # Generate a client id
-    clientId="$(shuf -en42 -- {a..z} {A..Z} {0..9} - _)"
-    # Fix the output from shuf so that it is a single string.
-    clientId="${clientId//[[:space:]]/}"
-    # Create the redirect uri, basically not needed here, but we need something
     redirectURI="file://$(realpath ${0})"
-    # Create the url to get the oauth token
-    local url="${instanceURL}/oauth/authorize?client_id=${clientId}&redirect_uri=${redirectURI}&response_type=code&scope=read%20write%20follow"
-    echo "Please open the following url in your browser."
-    echo "Copy the generated token, and paste it here."
-    echo
-    echo "${url}"
-    echo
+    # get client id and secret
+    curl -s -X POST -d client_name="${softwareName}" -d redirect_uris="://${redirectURI}" "${instanceURL}/api/v1/apps" |
+        jq 'to_entries | .[] | "export \(.key)='\''\(.value)'\''"' > "${configPath}/${configFile}"
 }
 
 
 # Variable initialization
 configPath="${XDG_CONFIG_HOME:-$HOME/.config}/ratatoskr" # Path for settings, usually ~/.config/ratatoskr
-configFile="default.token" # The default token, eventually will support multiple accounts.
+configFile="default.conf" # The default config file, eventually will support multiple accounts.
 softwareName="Ratatoskr" # The name of the client.
 
 
 # Main code starts here
+
+# make sure the configuration path exists:
+mkdir -p "${configPath}"
+
 get_oauth_token
+
 exit 0