4 files changed, 43 insertions, 14 deletions
diff --git a/Library/Homebrew/cask/lib/hbc/artifact/moved.rb b/Library/Homebrew/cask/lib/hbc/artifact/moved.rb
index 01e98ac35..eaaa49e20 100644
--- a/Library/Homebrew/cask/lib/hbc/artifact/moved.rb
+++ b/Library/Homebrew/cask/lib/hbc/artifact/moved.rb
@@ -31,20 +31,26 @@ module Hbc
 
         ohai "Moving #{self.class.artifact_english_name} '#{source.basename}' to '#{target}'."
         target.dirname.mkpath
-        FileUtils.move(source, target)
+
+        if target.parent.writable?
+          FileUtils.move(source, target)
+        else
+          SystemCommand.run("/bin/mv", args: [source, target], sudo: true)
+        end
+
         add_altname_metadata target, source.basename.to_s
       end
 
       def delete
         ohai "Removing #{self.class.artifact_english_name} '#{target}'."
-        return unless Utils.path_occupied?(target)
-
         raise CaskError, "Cannot remove undeletable #{self.class.artifact_english_name}." if MacOS.undeletable?(target)
 
-        if force
-          Utils.gain_permissions_remove(target, command: @command)
-        else
+        return unless Utils.path_occupied?(target)
+
+        if target.parent.writable? && !force
           target.rmtree
+        else
+          Utils.gain_permissions_remove(target, command: @command)
         end
       end
 
diff --git a/Library/Homebrew/cask/lib/hbc/container.rb b/Library/Homebrew/cask/lib/hbc/container.rb
index fc7246f3d..c6b2c3c37 100644
--- a/Library/Homebrew/cask/lib/hbc/container.rb
+++ b/Library/Homebrew/cask/lib/hbc/container.rb
@@ -4,6 +4,7 @@ require "hbc/container/bzip2"
 require "hbc/container/cab"
 require "hbc/container/criteria"
 require "hbc/container/dmg"
+require "hbc/container/executable"
 require "hbc/container/generic_unar"
 require "hbc/container/gzip"
 require "hbc/container/lzma"
@@ -39,6 +40,7 @@ module Hbc
         Gzip,  # pure gzip
         Lzma,  # pure lzma
         Xz,    # pure xz
+        Executable,
       ]
       # for explicit use only (never autodetected):
       # Hbc::Container::Naked
diff --git a/Library/Homebrew/cask/lib/hbc/container/executable.rb b/Library/Homebrew/cask/lib/hbc/container/executable.rb
new file mode 100644
index 000000000..848f6d4be
--- /dev/null
+++ b/Library/Homebrew/cask/lib/hbc/container/executable.rb
@@ -0,0 +1,18 @@
+require "hbc/container/naked"
+require "vendor/macho/macho"
+
+module Hbc
+  class Container
+    class Executable < Naked
+      def self.me?(criteria)
+        return true if criteria.magic_number(/^#!\s*\S+/)
+
+        begin
+          MachO.open(criteria.path).header.executable?
+        rescue MachO::MagicError
+          false
+        end
+      end
+    end
+  end
+end
diff --git a/Library/Homebrew/cask/lib/hbc/utils.rb b/Library/Homebrew/cask/lib/hbc/utils.rb
index 3fc817dd5..ecb565e8e 100644
--- a/Library/Homebrew/cask/lib/hbc/utils.rb
+++ b/Library/Homebrew/cask/lib/hbc/utils.rb
@@ -4,8 +4,7 @@ require "stringio"
 
 require "hbc/utils/file"
 
-PREBUG_URL = "https://github.com/caskroom/homebrew-cask/blob/master/doc/reporting_bugs/pre_bug_report.md".freeze
-ISSUES_URL = "https://github.com/caskroom/homebrew-cask#reporting-bugs".freeze
+BUG_REPORTS_URL = "https://github.com/caskroom/homebrew-cask#reporting-bugs".freeze
 
 # monkeypatch Object - not a great idea
 class Object
@@ -39,7 +38,15 @@ module Hbc
   module Utils
     def self.gain_permissions_remove(path, command: SystemCommand)
       if path.respond_to?(:rmtree) && path.exist?
-        gain_permissions(path, ["-R"], command, &:rmtree)
+        gain_permissions(path, ["-R"], command) do |p|
+          if p.parent.writable?
+            p.rmtree
+          else
+            command.run("/bin/rm",
+                        args: command_args + ["-r", "-f", "--", p],
+                        sudo: true)
+          end
+        end
       elsif File.symlink?(path)
         gain_permissions(path, ["-h"], command, &FileUtils.method(:rm_f))
       end
@@ -96,11 +103,7 @@ module Hbc
     def self.error_message_with_suggestions
       <<-EOS.undent
         Follow the instructions here:
-          #{Formatter.url(PREBUG_URL)}
-
-        If this doesn’t fix the problem, please report this bug:
-          #{Formatter.url(ISSUES_URL)}
-
+          #{Formatter.url(BUG_REPORTS_URL)}
       EOS
     end