diff --git a/Library/Homebrew/compat.rb b/Library/Homebrew/compat.rb
index b82a492f60..9a2cf29459 100644
--- a/Library/Homebrew/compat.rb
+++ b/Library/Homebrew/compat.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
 require "compat/cask/dsl/version"
+require "compat/language/python"
 require "compat/requirements/macos_requirement"
 require "compat/formula"
diff --git a/Library/Homebrew/compat/language/python.rb b/Library/Homebrew/compat/language/python.rb
new file mode 100644
index 0000000000..54784465ba
--- /dev/null
+++ b/Library/Homebrew/compat/language/python.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Language
+  module Python
+    class << self
+      module Compat
+        def rewrite_python_shebang(python_path)
+          Pathname.pwd.find do |f|
+            Utils::Shebang.rewrite_shebang(Shebang.python_shebang_rewrite_info(python_path), f)
+          end
+        end
+      end
+
+      prepend Compat
+    end
+  end
+end
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 1df01f60a6..4da0e79b41 100644
--- a/Library/Homebrew/formula.rb
+++ b/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
diff --git a/Library/Homebrew/language/perl.rb b/Library/Homebrew/language/perl.rb
new file mode 100644
index 0000000000..7368b36ee6
--- /dev/null
+++ b/Library/Homebrew/language/perl.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Language
+  module Perl
+    module Shebang
+      module_function
+
+      def detected_perl_shebang(formula = self)
+        perl_path = if formula.uses_from_macos_elements&.include? "perl"
+          "/usr/bin/perl"
+        elsif formula.deps.map(&:name).include? "perl"
+          Formula["perl"].opt_bin/"perl"
+        else
+          raise "Cannot detect Perl shebang: formula does not depend on Perl."
+        end
+
+        Utils::Shebang::RewriteInfo.new(
+          %r{^#! ?/usr/bin/(env )?perl$},
+          20, # the length of "#! /usr/bin/env perl"
+          perl_path,
+        )
+      end
+    end
+  end
+end
diff --git a/Library/Homebrew/language/python.rb b/Library/Homebrew/language/python.rb
index 5ec93a8a06..caaa6cb6a4 100644
--- a/Library/Homebrew/language/python.rb
+++ b/Library/Homebrew/language/python.rb
@@ -87,14 +87,26 @@ module Language
       ]
     end
 
-    def self.rewrite_python_shebang(python_path)
-      regex = %r{^#! ?/usr/bin/(env )?python([23](\.\d{1,2})?)?$}
-      maximum_regex_length = 28 # the length of "#! /usr/bin/env pythonx.yyy$"
-      Pathname(".").find do |f|
-        next unless f.file?
-        next unless regex.match?(f.read(maximum_regex_length))
+    # Mixin module for {Formula} adding shebang rewrite features.
+    module Shebang
+      module_function
 
-        Utils::Inreplace.inreplace f.to_s, regex, "#!#{python_path}"
+      # @private
+      def python_shebang_rewrite_info(python_path)
+        Utils::Shebang::RewriteInfo.new(
+          %r{^#! ?/usr/bin/(env )?python([23](\.\d{1,2})?)?$},
+          28, # the length of "#! /usr/bin/env pythonx.yyy$"
+          python_path,
+        )
+      end
+
+      def detected_python_shebang(formula = self)
+        python_deps = formula.deps.map(&:name).grep(/^python(@.*)?$/)
+
+        raise "Cannot detect Python shebang: formula does not depend on Python." if python_deps.empty?
+        raise "Cannot detect Python shebang: formula has multiple Python dependencies." if python_deps.length > 1
+
+        python_shebang_rewrite_info(Formula[python_deps.first].opt_bin/"python3")
       end
     end
 
diff --git a/Library/Homebrew/test/language/perl/shebang_spec.rb b/Library/Homebrew/test/language/perl/shebang_spec.rb
new file mode 100644
index 0000000000..5a59f162b7
--- /dev/null
+++ b/Library/Homebrew/test/language/perl/shebang_spec.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "language/perl"
+require "utils/shebang"
+
+describe Language::Perl::Shebang do
+  let(:file) { Tempfile.new("perl-shebang") }
+  let(:perl_f) do
+    formula "perl" do
+      url "https://brew.sh/perl-1.0.tgz"
+    end
+  end
+  let(:f) do
+    formula "foo" do
+      url "https://brew.sh/foo-1.0.tgz"
+
+      uses_from_macos "perl"
+    end
+  end
+
+  before do
+    file.write <<~EOS
+      #!/usr/bin/env perl
+      a
+      b
+      c
+    EOS
+    file.flush
+  end
+
+  after { file.unlink }
+
+  describe "#detected_perl_shebang" do
+    it "can be used to replace Perl shebangs" do
+      allow(Formulary).to receive(:factory).with(perl_f.name).and_return(perl_f)
+      Utils::Shebang.rewrite_shebang described_class.detected_perl_shebang(f), file
+
+      expected_shebang = if OS.mac?
+        "/usr/bin/perl"
+      else
+        HOMEBREW_PREFIX/"opt/perl/bin/perl"
+      end
+
+      expect(File.read(file)).to eq <<~EOS
+        #!#{expected_shebang}
+        a
+        b
+        c
+      EOS
+    end
+  end
+end
diff --git a/Library/Homebrew/test/language/python_spec.rb b/Library/Homebrew/test/language/python_spec.rb
index a474e04da6..174373d999 100644
--- a/Library/Homebrew/test/language/python_spec.rb
+++ b/Library/Homebrew/test/language/python_spec.rb
@@ -2,6 +2,7 @@
 
 require "language/python"
 require "resource"
+require "utils/shebang"
 
 describe Language::Python, :needs_python do
   describe "#major_minor_version" do
@@ -32,6 +33,48 @@ describe Language::Python, :needs_python do
   end
 end
 
+describe Language::Python::Shebang do
+  let(:file) { Tempfile.new("python-shebang") }
+  let(:python_f) do
+    formula "python" do
+      url "https://brew.sh/python-1.0.tgz"
+    end
+  end
+  let(:f) do
+    formula "foo" do
+      url "https://brew.sh/foo-1.0.tgz"
+
+      depends_on "python"
+    end
+  end
+
+  before do
+    file.write <<~EOS
+      #!/usr/bin/env python3
+      a
+      b
+      c
+    EOS
+    file.flush
+  end
+
+  after { file.unlink }
+
+  describe "#detected_python_shebang" do
+    it "can be used to replace Python shebangs" do
+      expect(Formulary).to receive(:factory).with(python_f.name).and_return(python_f)
+      Utils::Shebang.rewrite_shebang described_class.detected_python_shebang(f), file
+
+      expect(File.read(file)).to eq <<~EOS
+        #!#{HOMEBREW_PREFIX}/opt/python/bin/python3
+        a
+        b
+        c
+      EOS
+    end
+  end
+end
+
 describe Language::Python::Virtualenv::Virtualenv do
   subject { described_class.new(formula, dir, "python") }
 
diff --git a/Library/Homebrew/test/resource_spec.rb b/Library/Homebrew/test/resource_spec.rb
index ec21741f08..fd4e591014 100644
--- a/Library/Homebrew/test/resource_spec.rb
+++ b/Library/Homebrew/test/resource_spec.rb
@@ -157,7 +157,7 @@ describe Resource do
   end
 
   specify "#verify_download_integrity_mismatch" do
-    fn = double(file?: true)
+    fn = double(file?: true, basename: "foo")
     checksum = subject.sha256(TEST_SHA256)
 
     expect(fn).to receive(:verify_checksum).with(checksum)
diff --git a/Library/Homebrew/utils/shebang.rb b/Library/Homebrew/utils/shebang.rb
new file mode 100644
index 0000000000..eda6eec190
--- /dev/null
+++ b/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