def search_text(file, text, new_text): f = open(file, 'r') content = f.read() print(text, content.find(new_text)) content = content.replace(text, new_text) f.close() with open(file, 'w') as f: f.write(content) file = './plugins/02-connection.js' text1 = "mode = 'dev'" newtext1 = "mode = 'prod'" search_text(file, text1, newtext1)