utils/shebang: add rewrite_shebang

Library/Homebrew/formula.rb

@@ -6,6 +6,7 @@ require "lock_file"
 require "formula_pin"
 require "hardware"
 require "utils/bottles"
+require "utils/shebang"
 require "utils/shell"
 require "build_environment"
 require "build_options"
@@ -50,6 +51,7 @@ require "find"
 class Formula
   include FileUtils
   include Utils::Inreplace
+  include Utils::Shebang
   include Utils::Shell
   extend Enumerable
   extend Forwardable

Library/Homebrew/utils/shebang.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module Utils
+  module Shebang
+    module_function
+
+    class RewriteInfo
+      attr_reader :regex, :max_length, :replacement
+
+      def initialize(regex, max_length, replacement)
+        @regex = regex
+        @max_length = max_length
+        @replacement = replacement
+      end
+    end
+
+    def rewrite_shebang(rewrite_info, *paths)
+      paths.each do |f|
+        f = Pathname(f)
+        next unless f.file?
+        next unless rewrite_info.regex.match?(f.read(rewrite_info.max_length))
+
+        Utils::Inreplace.inreplace f.to_s, rewrite_info.regex, "#!#{rewrite_info.replacement}"
+      end
+    end
+  end
+end