Resolved a problem for linux users

BIDSHandler/CreationTool/Application.py

@@ -2,6 +2,7 @@ import json
 import os
 import shutil
 import tkinter as tk
+import platform
 from pathlib import Path
 from tkinter import ttk, messagebox
 
@@ -554,8 +555,12 @@ class Application(tk.Frame):
                                              command=self.actual_project_state)
         self.show_project_button.pack()
 
+        if platform.system() == 'Windows':
             open_project_button = tk.Button(self.integrate_sidecar_frame, text='Open project',
                                         command=lambda: os.startfile(self.project_directory))
+        else:
+            open_project_button = tk.Button(self.integrate_sidecar_frame, text='Open project',
+                                        command=lambda: os.system('xdg-open ' + self.project_directory))
         open_project_button.pack()
 
         self.previous_directory = None