String Template Renderer

Given a template file and a variables file, render the template by substituting each {{KEY}} placeholder with its value.

Input

Two arguments: the path to the template file, then the path to the variables file.

The template contains zero or more placeholders of the form {{KEY}}. The variables file has one KEY=VALUE setting per line, e.g.:

NAME=Alice
BALANCE=$100.50
[email protected]

Output

Print the template with every {{KEY}} replaced by its value:

• If KEY exists in the variables file, replace the placeholder (braces included) with its value, used exactly as written — values may contain any character, including $, ., /, &, or %, and must be substituted literally, not treated as part of a pattern.
• If KEY does not exist in the variables file, leave the placeholder (including the braces) unchanged.
• The same placeholder may appear more than once in the template, and should be replaced every time it appears.

Constraints

• The template has at most 100,000 lines.
• KEY consists only of letters, digits, and underscores.
• A {{...}} placeholder never spans more than one line.
• Keys in the variables file are unique; values never contain a newline, but may otherwise contain any character.

Example

Template:

Hello {{NAME}}, your balance is {{BALANCE}}.
Contact: {{EMAIL}}

Variables:

NAME=Alice
BALANCE=$100.50
[email protected]

Output:

Hello Alice, your balance is $100.50.
Contact: [email protected]