Before the Shadow Play

Tag: how-to

  • Samsung SMH7178SME charcoal filter replacement tip

    I’ve been in my new condo for 4 months now, and as always when you move into a place, you keep finding out things. I now know what the mystery switch in the hall is supposed to do: it’s for a wall sconce that the previous owner removed from the dining room wall. This results in their being no lighting at all in the dining room other than light from the kitchen. The wall sconce at the bottom of the stairs to the upper bedroom was very pretty, but it was open at the top, so if you turned on the light to go downstairs at night, you got bare bulb right in the eye. I’ve since replaced it with a nice cylindrical fixture from Lowe’s that is closed at the top. The light switches feel a bit worn, and I’ve been replacing them one by one with the flat rocker-style switches, which fit the modern style of the place better anyway.

    I also have an over-the-stove microwave that vents inside rather than out. Not optimal, but I’m used to that from my old place in Redwood Shores, so this isn’t a big deal. It’s a Samsung model SMH7178SME, very pretty – all stainless steel, with a cute little flap that tilts out when the vent fan’s running, and closes when it’s not so you have a smooth continuous surface when it’s off. Feature-wise, I prefer the GE models, but this one is perfectly fine, if a bit on the high-powered side.

    Being at the personal altitude I am, I couldn’t help noticing that when the fan was running, I could see that the grille inside the flap was fairly gunked up with dust trapped in greasy residue. That didn’t seem right, so I (finally) this week downloaded the manual to check out the right way to clean it.

    After reading through, I discovered another little gotcha from he previous owner: both the grease filters and the charcoal filter were missing. (I’m guessing they were horrible and she just removed then instead of replacing them. Very much in line with just removing the wall sconce and conveniently forgetting there was a $2000 bill for deck repairs she hadn’t paid.)

    I was able to pick up replacements from PartSelect.com (half the price of Sears Parts Direct – sorry, Sears!). They sent the filters in a bubble envelope, which wasn’t really quite enough protection. The filters got bent up a bit in transit. I was able to straighten the grease filters out sufficiently to get them to fit properly, and the charcoal filter was hefty enough that it was okay.

    Installing it, however, was a different issue altogether. The manual says you need to remove two screws at the top of the microwave and then “pull off the grille” to access the place where the filter goes. It leaves out that you need to push the grille to the left first to get the tabs at the bottom to unseat!

    Once this is done, you can simply pull the whole grille assembly off toward you to pop it off the front of the microwave, and follow the rest of the instructions from the manual – there’s a little place to plop the filter into, where it sits at an angle, tilted toward you.

    Putting the grille back was challenging until I hit on opening the flap so I could see inside and line up the bottom tabs; after that it was less than a minute to all back together again.

    I’ll try it out later today when I make a batch of pasta sauce and see how well it works to disperse odors. I don’t mind my house smelling of good food; I just like the choice of whether it does or not.

  • xmonad on OS X Mavericks

    I installed XQuartz today, and while looking around for a low-distraction window manager, I came across xmonad. It looked interesting, and I started following the installation instructions and found they were out of date. Here’s an updated set of instructions for installing xmonad.

    1. Install XQuartz.
    2. Install homebrew if you don’t already have it.
    3. brew update
    4. brew install ghc cabal-install wget
    5. cabal update
    6. export LIBRARY_PATH=/usr/local/lib:/usr/X11/lib
    7. cabal install xmonad
    8. Launch XQuartz and go to Preferences (command-,). Set the following:
      •  Output
        • Enable “Full-screen mode”
      •  Input
        • Enable “Emulate three button mouse”
        • Disable “Follow system keyboard layout”
        • Disable “Enable key equivalents under X11”
        • Enable “Option keys sent Alt_L and Alt_R”
      •  Pasteboard
        • Enable all of the options

    monad has been installed in $HOME/.cabal/bin/xmonad. You now need to create an .xinitrc that will make XQuartz run monad. Edit ~/.xinitrc and add these lines:

    [[ -f ~/.Xresources ]] && xrdb -load ~/.Xresources
xterm &
$HOME/.cabal/bin/xmonad

    You can now launch XQuartz; nothing seems to happen, but press command-option-A and the xmonad  “desktop” (one huge xterm) will appear, covering the whole screen. Great! It’s using the default teeny and nasty xterm font, though. Let’s pretty it up a bit by making it use Monaco instead. Edit ~/.xresources and add these lines:

    xterm*background: Black
xterm*foreground: White
xterm*termName: xterm-color
xterm*faceName: Monaco

    Quit XQuartz with command-Q, and then relaunch, then hit command-option-A again to see the XQuartz desktop. The terminal should now be displaying in Monaco.

    At this point, you should take a look at the guided tour and get familiar with xmonad. If you’re looking for a distraction-free working environment, this might be good for you. I’m going to give it a try and see how it works out.

  • Shellshock scanner

    So I had a bunch of machines with a standard naming convention that I needed to scan for the Shellshock bug. Since I just needed to run a command on each one and check the output, and I had SSH access, it seemed easy enough to put together a quick script to manage the process.

    Here’s a skeleton of that script, with the details on what machines I was logging into elided. This does a pretty reasonable job, checking 300 machines in about a minute. You need to have a more recent copy of Parallel::ForkManager, as versions prior to 1.0 don’t have the  ability to return a data structure from the child.

    $|++;
use strict;
use warnings;
use Parallel::ForkManager 1.07;

my $MAX_PROCESSES = 25;
my $pm = Parallel::ForkManager->new($MAX_PROCESSES);
my @servers = @SERVER_NAMES;
my %statuses;
my @diagnostics;
$pm-> run_on_finish (
    sub {
        my($pid, $exit_code, $ident, $exit_signal, $core_dump,
           $data_structure_reference) = @_;
        if (defined($data_structure_reference)) { 
            my ($host_id, $status, $results) = @{$data_structure_reference};
            if ($status eq 'Unknown') {
                push @diagnostics, $host_id, $results;
            } else {
                push @{ $statuses{$status} }, $host_id;
            }
        } else { 
            warn qq|No message received from child process $pid!\n|;
        }
    }
);

print "Testing servers: ";
for my $host_id (@servers) {
    my $pid = $pm->start and next;
    my $result = << `EOF`;
ssh -o StrictHostKeyChecking=no $host_id <<'ENDSSH' 2>&1
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
ENDSSH
EOF
    my $status;
    if ($result =~ /Permission denied/is) {
       $status = q{Inacessible};
    } elsif ($result =~ /key verification failed/s) {
       $status = q{Key changed};
    } elsif ($result =~ /timed out/is) {
       $status = q{Timed out};
    } elsif ($result =~ /vulnerable/s) {
           $status = q{Vulnerable};
    } elsif ($result =~ /ignoring function definition attempt/s) {
       $status = q{Patched};
    } elsif ($result =~ /Name or service not known/s) {
       $status = q{Nonexistent};
    } else {
       $status = q{Unknown}
    }
    print "$host_id, ";
    $pm->finish(0, [$host_id, $status, $result]);
}
$pm->wait_all_children;
print "done!\n";
for my $status (keys %statuses) {
    print "$status: ",join(',', @{$statuses{$status}}), "\n";
}
print "The following hosts returned an undiagnosed status:",
      join("\n", @diagnostics), "\n";

    Note that this doesn’t test the most recent version (#3) of the bug; I have modified it slightly to test for that, but that’s a reasonable exercise for the reader.