Yeraze's Domain 3.0

• Support for Google Hangouts links!
• Support for Google Calendars Availability data!

• Cabs/Taxis - During the entire trip, we couldn’t find a Taxi that would accept American dollars nor credit cards. When we did try to use local currency, we found we were getting ripped off with strange fee’s that couldn’t (or wouldn’t) be explained in English. The solution: Gett . It’s basically Uber for Taxi’s, but it works in Tel-aviv and will directly charge your selected credit card without issue. I used it numerous times. I never waited more than 10 minutes for a ride (usually less than 5), and once you are at your destination you simply say thanks and step out. Easy, simple, and they won’t (or can’t) rip you off.
• Food - Oh my god the food is amazing. During our stay we ate at several places and each one was more impressive than the last. However, it’s massive and it’s heavy. Apparently it’s an arabian tradition to serve appetizers (without ordering, I think, like chips & salsa at a mexican restaurant) consisting of vegetables. They’ll come in tiny dishes, only 0.5-1 cup each, but you’ll get a dozen or more of things like pickles, coleslaw, carrots, peas, and lots of other things I wasn’t able to identify but tasted great. And when you finish them, they’ll bring more. And they’ll keep bringing more until your real meal arrives. So prepare to be stuffed like a thanksgiving turkey after every meal.
• Electricity - Of course, Israel runs at a different voltage and uses a different plug adapter than the US. Most “smart" devices (cell phones, computers, game systems, etc) will automatically adapt with a plug adapter, but other dumb devices (like electric shavers, as my traveling companion discovered) will burn up. I recommend getting the Kensington All-in-one Adapter ($13 on Amazon) and a small power strip (I like the Monster Travel Strip for $20), which will then let you turn 1 Israeli outlet into 4 US outlets, suitable for charging all your stuff overnight. And if you plan to use or charge any of the “dumb" devices, buy a transformer (I don’t have one, so I can’t really recommend anything).
• Coffee - If you’re a big coffee drinker, you might have a rough time. I don’t think I saw a single cup of coffee the whole trip. The big thing there is espresso, available as an after-dinner beverage in every restaurant. In most businesses, the big thing seems to be Nespresso. It’s like the Israeli version of the Keurig: Little disposable capsules that make tiny little cups of espresso. So be wary: It’s only a quarter of the size of your typical american coffee, but it packs the same punch. Don’t overdo it.
• Driving - Driving in that corner of the globe is very unlike the US. It’s not “aggressive", but traffic laws seems be much more.. umm.. “liberally interpreted" than in the US. I didn’t drive, but in all of the cabs we took you would see people cutting each other off, weaving in lanes, 3-cars wide in 2-lanes, etc. Nobody was upset, or even surprised by it, it’s just normal. And I never witnessed a single accident. However, as someone who has always suffered from motion sickness in cars, I would recommend you prepare for the worst if you’re the same: The sudden stops and stress from the unexpected behavior of it all was rough for me.
• Airport - Anyone who’s familiar with the history of the region shouldn’t be surprised to find that the security at the airport is tight. Flying into Israel was pretty uneventful: Talk to the passport officers, get a printed Visa, and all done. Returning home was different. Before even entering the airport we were approached by security and quizzed about our bags. Later, we had to repeat the process about twice more before we were even allowed near the x-ray machines. At the machines, they very carefully control the lines so that only 1 person is near it at a time and they require all electronics to be removed from the bags. I misunderstood at first and almost got in trouble, so let me repeat that for you: all electronics. That’s cables, chargers, batteries, plug adapters, electric razors, toothbrushes. All. And it’s slow, they check it all carefully. After talking to some locals and other travelers, I think some of this process may be randomized and customized, changing daily and based on your reaction. So prepare to spend some time when you get ready to return to the US.

In a funny bit of coincidence, I'm currently on a Delta flight with Gogo wireless as I see this story about Gogo and SSL certificates break. The allegation is that Gogo is intercepting SSL traffic, decrypting, doing who-knows-what, then re-encrypting before delivering it to you. It's a pretty common practice in most companies where they want to monitor employee behavior, but it typically requires that someone installs a special root certificate on your machine. Otherwise, most modern browsers will throw all kinds of warnings and blocks about the site being untrusted.

So, I loaded up "SSL Detective" (a free iOS app) on my iPhone and went to work. My findings are interesting, but a bit weird.

Basically, all the usual stuff (Twitter, Facebook, Google, Gmail) was just fine. But video sites (YouTube, Vimeo, Crackle) all show up signed by this one strange cert.

It's a pretty strange thing to be analyzing, as there's probably no personal data going there (at least in comparison to decrypting Facebook or gmail). My guess is that it's related to their desire to block streaming video sites.

From what I know, most Flash and JavaScript will die if they attempt to pull data and the certificate doesn't check out. So this is a mostly effective, albeit odd, way to block it. I don't know why they don't just rewrite the DNS entries somewhere with a warning banner ("Don't do this, be kind to your network using neighbors") or just block the IP.

But I thought it interesting enough to share my findings.

Using GDB to debug programs is great and all, but if you work with Scientific data then one really critical function is the ability to plot a long array or vector, to see how the solution is evolving at various stages.

After a bit of tinkering, I was able to take this code snippet and modify it for my needs. It had just a few problems:
The syntax they used for labeling things fell apart when I was using Eigen vectors, the -> became shell redirects.
It didn’t link very long (100+) entry arrays.

So I modified it like so:

# plot1d.gdb

#
# Copyright (C) 2008 Florian Lorenzen
# - Taken from https://sourceware.org/gdb/wiki/PlottingFromGDB
# Modified by Randall Hand to actually make it work.
# original version seemed to badly handle variable names
# like esf->data[0]@1024 (turning the > into a pipe redirect)
#
# Plot an expression that expands to {x1, x2, ..., xN}, i. e.
# N numbers using gnuplot.
#
# This file is for the GNU debugger 6.x.
#
# It writes temporary files named __plot1d.dump, __plot1d.dat, __plot1d.gp, so
# you should not have files of the same name in the working directory.
#
# It requires sed, awk, and gnuplot available in the $PATH.

# plot1d_opt_range   
#
# Plot the points of  passing  as plot options using
#  in the set yrange command.
define plot1d_opt_range
shell rm -f /tmp/__plot1d.dump /tmp/__plot1d.dat /tmp/__plot1d.gp
set logging file /tmp/__plot1d.dump
set logging on
set logging redirect on
set height 0
set print elements unlimited
output $arg0
set logging off
set logging redirect off
shell awk '{printf("%s", $0)}' < /tmp/__plot1d.dump | \
sed 's/^{\(.*\)}$/\1/;s/, */\n/g' > /tmp/__plot1d.dat
shell echo 'plot "/tmp/__plot1d.dat" title "$arg0"; pause -1 "Press enter to continue"' > /tmp/__plot1d.gp
shell gnuplot /tmp/__plot1d.gp
# shell rm -f /tmp/__plot1d.dump /tmp/__plot1d.dat /tmp/__plot1d.gp
end

# plot1d 
#
# Just plot the points of .
define plot1d
plot1d_opt_range $arg0 "" "[*:*]"
end

# plot1d_opt  
#
# Plot the points of  passing  to the
# plot command after the datafile. So, one can pass
# "with lines" here.
define plot1d_opt
plot1d_opt_range $arg0 $arg1 "[*:*]"


end

With this file placed somewhere and executed, you can then simply do plot1d data[0]@128 to get a nice plot of the first 128 values of data.

And if you like it so much you want to keep it, simply add source plot1d.gdb (which a path to wherever you put it) to your ~/.gdbinit

For the last several years, "ransomware" has been one of the bigger problems on the internet. Half computer virus, half phishing attempt, it's the frustrating encryption or theft or personal data that can only be recovered by paying the attacker some nominal sum to get things restored.. It's incredibly annoying, but good antivirus and security measures can generally protect people. Personally, I've never dealt with it but it seems to pop up in the news every few months.
However, now it seems hackers have taken Ransomware to a whole new level. Earlier today, SVN hosting webservice "Code Spaces" was shut down when an attacker demanded money for return of their Amazon EC2 control panel, and when they tried to stop him (by doing exactly what I would have done: Changing passwords and removing access) he irreversibly erased all of their custom data and repos! Similarly the same thing almost happened to Feedly but they were more successful in averting disaster. Evernote got hit with a DDOS as well, but (as far as they are reporting) there was no extortion attempt.
Whether or not these incidents are related, it's a scary time.. For the last several years, lots of people have migrated data to the cloud. Documents and communications exist in Google services, backups exist in Carbonite & Crashplan, personal memories exist in Flickr and Instagram, bits of data exist in services like GitHub and Evernote. When suddenly the cloud is no safer than your personal computer, maybe it's time to start moving more towards "personal clouds" ?

I’ve been writing lots of bash scripts lately, so I thought it would be a good idea to document a few of the little tricks I’ve been using.

First off, to make a script that has to be executed in bash:

#!/bin/bash

if [ ! "$BASH_VERSION" ] ; then
  echo "Please do not use sh to run this script ($0), just execute it directly" 1>&2
  exit 1
fi

This was needed for a script that makes uses of Bash syntax for for loop and some basic math, and I had a user reporting errors when they tried to do sh script.sh. sh ignores the opening #!/bin/bash line and tries to execute the script directly, and fails when it hits those lines.

Then, to make a script that has to be sourced in the global environment (to set environment variables like PATH and LD_LIBRARY_PATH for the user).

#!/bin/bash

if [[ "$(basename "$0")" == "script.sh" ]]; then
  echo "ERROR: Don't run $0, source it" >&2
  exit 1
fi

replace script.sh with the name of the actual file.

Then, to URL Encode a parameter in bash (I used this to encode a user provided git password into the url), use this function:

rawurlencode() {

  local string="${1}"
  local strlen=${#string}
  local encoded=""

  for (( pos=0 ; pos
    c=${string:$pos:1}
    case "$c" in
      [-_.~a-zA-Z0-9] ) o="${c}" ;;
      * )               printf -v o '%%%02x' "'$c"
    esac
    encoded+="${o}"
  done
  echo "${encoded}"    # You can either set a return variable (FASTER)
  REPLY="${encoded}"   #+or echo the result (EASIER)... or both... :p
}

Then you can use it like so:

echo Enter your GitHub username:

read GIT_USER

echo Enter your GitHub Password:
read GIT_PASSWORD

GIT_AUTH=$( rawurlencode "${GIT_USER}" ):$( rawurlencode "${GIT_PASSWORD}" )

git clone http:[email protected]/user/repo

yeah yeah, I know.. SSH keys are better… tell it to the users, not me

Finally, using getopt. It’s a big tool, but the basics of using it:

USE_SSH=0
AUTOMATED=0
BUILD_WIDTH=1

while getopts "aj:s" o; do
    case "${o}" in
        s)
            USE_SSH=1
            ;;
        a)
            AUTOMATED=1
            ;;
        j)
            BUILD_WIDTH=${OPTARG}
            ;;
        *)
            usage
            ;;
    esac
done
shift $((OPTIND-1))

Important bits:

• the getopts line: Include each character recognized as a flag, and following it with a : if it requires an argument.
• Then include a case for each one in the big switch.. use $(OPTARG) to get the argument, if it’s needed.

Makes argument parsing simple in bash scripts simple… Also define a usage function to spew out the supported options, and you’re golden.