Overwrite Unity default template in one command.

fix_unity_template.py

# 1. Change the path to Unity Editors in the path_to_unity variable below.
# 2. Put the template you wish to use in the template_content variable.
# 3. Run a command like this: python unity_dark_theme.py 2019.3.3f1

import sys


if len(sys.argv) != 2:
    sys.exit("Provide a Unity version as an argument.")

unity_version = sys.argv[1]

# Change to the path to Unity Editors you are actually using.
path_to_unity = 'c:/Program Files/Unity Editors/{}/Editor'.format(unity_version)

# Change to the template you would like to use.
template_content = '''using UnityEngine;

public class #SCRIPTNAME# : MonoBehaviour
{

}

'''

template_path = sys.path.join(path_to_unity,
    'Editor/Data/Resources/ScriptTemplates/81-C# Script-NewBehaviourScript.cs.txt')

try: 
    with open(template_path, 'w') as template:
        template.write(template_content)
except IOError:
    sys.exit("No such path to Unity, or this version of Unity is not installed.")

print("Template content overwritten successfully.")