Protip on traviscj/blog

loan trickery

Thu, 27 Mar 2025 10:36:04 -0500

I have this “American Express Blueprint Business Loan” product to have a line of credit for the rentals if I’m ever in a pinch.

They allow up to $21,700 with this very easy application process, you basically just slide a slider to the amount needed & select between 6, 12, 18, 24 months:

This shows a schedule like this:

Looking at this, there’s a lot of temptation to think

hype channels

Mon, 23 Aug 2021 21:20:31 -0500

When I was managing a small team, one of the coolest protips I came across was the idea of a “hype channel”. This builds on the idea of a “hype doc” by changing the medium: instead of writing into a document, you write blurbs on your own private Slack channel.

I’m not sure whether this would help anyone but me, but maybe it’ll help someone else drowning in Chrome tabs?

more light, better pictures

Sat, 05 Jan 2019 00:00:00 +0000

We were trying to take some Christmas pictures but feeling a bit unsatisfied with the way the pictures were coming out:

I wanted some flash or something, but the batteries on all the “better” cameras were already dead, so I went looking for an alternative. We tried to get the overhead light turned on, but couldn’t find the switch for that.

The next-closest source of light was a sheet music lamp on my mom’s piano! Borrowing that for the cause, I was able to get this one instead:

watching progress in mysql

Fri, 04 Jan 2019 00:00:00 +0000

Pretty frequently at work, I end up polling a database with some command like

SELECT MAX(id) FROM my_tbl;
SELECT MAX(id) FROM my_tbl;
SELECT MAX(id) FROM my_tbl;
SELECT MAX(id) FROM my_tbl;
-- .... ad nauseam ....

I’ve eventually noticed a few patterns I use pretty consistently:

estimate ETA by including `NOW()`/`UNIX_TIMESTAMP()`

Generally, the point of hovering over the table is to get an estimate of when it will finish/catch up/whatever. For that, you generally want to include a timestamp in the query output, so when you come back a while later, you can know exactly how much time has elapsed. I might transform the above query into

moar stupid jquery tricks

Tue, 23 Oct 2018 00:00:00 +0000

Sometimes it’s useful to use tampermonkey on a site without nice ids for the elements you want to edit. It turns out it’s still pretty easy!

Take my own website; I have <h2> elements for the headers, but none of them have any ids associated. But as discussed in the jquery selectors post, we can still select by just the tag, with a selector like

$("h2")

This returns a jQuery object, which behaves like an array. If we want to select a particular one – like “Research Interests” – we can try accessing different elements until we get the one we want:

killing all timeouts in js

Wed, 17 Oct 2018 20:43:04 +0000

this article has a nice trick for killing all javascript timeouts:

function stopAllTimeouts() {
    var id = window.setTimeout(null, 0);
    while (id--) {
        window.clearTimeout(id);
    }
}

which can be entered on the javascript console and then run with

stopAllTimeouts()

This is an effective way to prevent javascript timeouts from doing a whole variety of things, like

carousels
endless scrolls
any other kind of animations

jquery selectors

Wed, 17 Oct 2018 03:51:27 +0000

This is silly, but I always forget this:

I also learned you can specify things like

// @require https://code.jquery.com/jquery-2.1.4.min.js

in a Tampermonkey script, even when a given site doesn’t already have jquery.

guava RangeMap

Fri, 26 Jan 2018 09:52:41 +0000

We had some code like this:

NavigableMap<Double, Integer> PRIORITY_MULTIPLIERS = new TreeMap<Double, Integer>() {{ "{{ " }}
  put(LOW_THRESHOLD, 1);    // (20k..40k)  => 1
  put(MEDIUM_THRESHOLD, 2); // [40k..100k) => 2
  put(HIGH_THRESHOLD, 3);   // [100k..+∞)  => 3
}};

Integer getPriorityMultiplier(Double v) {
  if (v < LOW_THRESHOLD) {
    return 0;
  }
  return PRIORITY_MULTIPLIERS.floorEntry(v).getValue()
}

I replaced with a [RangeMap][RangeMap] that uses [Range][Range] instances as keys: [RangeMap]: https://google.github.io/guava/releases/16.0/api/docs/com/google/common/collect/RangeMap.html [Range]: https://google.github.io/guava/releases/16.0/api/docs/com/google/common/collect/Range.html

RangeMap<Double, Integer> PRIORITY_MULTIPLIERS = ImmutableRangeMap.<Double, Long>builder()
      .put(Range.lessThan(LOW_THRESHOLD), 0)
      .put(Range.closedOpen(LOW_THRESHOLD, MEDIUM_THRESHOLD), 1)
      .put(Range.closedOpen(MEDIUM_THRESHOLD, HIGH_THRESHOLD), 2)
      .put(Range.atLeast(HIGH_THRESHOLD), 3)
      .build();
Integer getPriorityMultiplier(Double v) {
  return rangePriorityMultipliers.get(v);
}

Advantages here being:

everything has a failure rate

Wed, 03 Jan 2018 07:09:49 +0000

I was happily riding in to work this morning on my motorcycle. Periodically while riding, a spark of terror that I’ve forgotten to buckle my backpack to the bike’s frame hits me. So frequently, in fact, that I’ve grown used to reaching behind me to feel for the backpack in a spare second when I don’t need to clutch.

Today was different:

I reached for the backpack but felt nothing.

extracting the last few dollars from Visa/MC gift cards

Tue, 02 Jan 2018 00:00:00 +0000

Once in a while, I get a prepaid gift card like this:

They’re – like money – great! But they do have one downside: it’s hard to spend the change once you’ve bought off most of the value.

Originally this was going to be a quick “just redeem it with Amazon’s gift card” post, but a bit of study revealed that it isn’t quiet that simple:

the authorized amount can prevent the full transaction from going through, so if it’s the first transaction at Amazon, you might need to leave $1.00 to cover the reserve.
the article mentions a $5 minimum, but the initial amount & card selection on Amazon doesn’t seem to have a problem with lower amounts, so YMMV I guess.

The article also mentions a different solution that I should have thought of: apparently some banks will redeem the value of the card into your account. You just need to show up at a branch of your bank with proper identification.

things you don't learn in grad school

Mon, 01 Jan 2018 00:00:00 +0000

oncall exists.
the data is never available how you need it.
unit tests matter.
pushing code after 3pm is risky if you’re not willing to work all night. (courtesy Paul Joos)

url encoding safe relational operators

Wed, 29 Nov 2017 07:55:04 +0000

I was catching up on Jesse Wilson’s blog this morning, and in particular his post URL Encoding Is Material. In that article, he says

My advice

If you’re defining your own URLs, you’ll save a lot of trouble by avoiding characters like <, >, {, }, +, ^, &, |, and ;.

I came across this problem in one of my projects at work: I wanted a page to display some recent records with 1) a name field provided by the user and 2) a value field that match $l \leq \text{value} \leq b$, where $l$ and $b$ are given by the user. I also wanted that page to have a URL representing that condition, so that it could be easily shared with teammates and soforth. When I started working on it, I didn’t have Jesse’s wisdom, and so I naively came up with a URL structure something like

_useful

Mon, 03 Apr 2017 00:00:00 +0000

I often create a directory/file called _useful/_useful.org/_useful.txt. I have one in my Dropbox, for example, that contains:

My apartment lease
My car/motorcycle insurance details
A textfile with my vehicle plate numbers/VINs/insurance policy numbers.

At work, I have one with

the top visited links for logs/metrics/admin interfaces for the services I work with most
a list of links of “typical” or “exemplar” things
- links to our internal tool views for typical payments, merchants, etc
- typical size (in bytes) of various protobuf messages we use a lot, size of 1M messages, #messages in 1MB/GB
common coding idioms, like several variants of @RunWith that we use in various cases in our test code.
useful commands for doing stuff (curl/SQL/plain old shell)

Plain text is great for all the reasons it usually is. But it’s especially useful here (see what I did there?) because the file loads much faster than Google Docs or wiki pages, it’s grep-able, it’s trivial to copy to a new machine, there’s no fuss about futzing with the document to get it to format properly, and soforth.

.sqliterc

Fri, 31 Mar 2017 00:00:00 +0000

I came across Better output from sqlite3 command line. His .sqliterc file did not work for me, but the simpler

.mode "column"
.headers on

did work nicely.

I also found out that brew install sqlite3 does not install the sqlite3 binary to $PATH, which stinks.

The sqlite3 environment is still much less pleasant than the mysql cli. A few things on my wishlist:

tab completion of tables, fields, keywords, and functions.
nicer .schema output – I’ve just gotten really used to reading them in mysql output

It sounds like maybe apsw can be something useful? Or maybe Navicat? (but that’s expensive)

use the `locale.currency` library function

Fri, 20 Jan 2017 00:00:00 +0000

I had stupidly written a pair of functions like this:

def comma_sep(amount):
    thousands = int(amount/1000)
    remainder = int(amount%1000)
    if thousands > 0:
        return comma_sep(thousands)+","+"%.3d"%(remainder)
    else:
        return str(remainder)
def friendly_from_cents(total_cents):
    pos = total_cents >= 0
    total_cents = abs(total_cents)
    cents = int(total_cents%100)
    dollars = int(total_cents/100)
    friendly = "$"+comma_sep(dollars)+"."+str(cents)
    if pos:
        return friendly
    else:
        return "-" + friendly

This is stupid, because python has builtin support to localize currency:

import locale
locale.setlocale(locale.LC_ALL, 'en_US')
locale.currency(-1800, grouping=True)

I think it’s tempting to fall into these traps, because it always starts simpler: I had some total_cents variable and just wanted to display quick and dirty. The complexity built up gradually, until I had something pretty complicated. Oops.

motorcycle learnings at 250 miles

Fri, 02 Dec 2016 00:00:00 +0000

Two new learnings at the 250mi point:

The backpack straps down to the back!

![]({{ site.baseurl }}/assets/backpack_straps_s.jpg)

The balance of the bike feels so much better with the backpack low and riding without weight on my shoulders is so much more comfortable.
Ear Plugs are amazing! I noticed earplugs being worn on The Long Way Round and decided to try it out. It is really surprising how relevant noises (other cars, etc) make it through fine, but how much nicer it is to not have the wind noise!

Useful homebrew formula

Thu, 01 Dec 2016 00:00:00 +0000

Last week I was telling Paul about things I have brew installed on my work laptop. I pulled a full list as I was doing some upgrades and stuff this morning.

Glancing over it a bit, here are some of my favorites/most usefuls:

autojump for a usage-adjusting cd – given a partial string it just goes to the most-used directory with that prefix. I have autojump aliased to j to shorten it up even more.
colordiff to make diffs/grep/etc nicer to look at in the terminal.
coreutils/dateutils is nice because it installs the GNU versions of a lot of standard linux commands like du and ls and date that work a bit strange/differently on OSX.
jq is amazing — lets you query JSON objects.
ledger to manage bank balances in plain text.
newsbeuter to subscribe to RSS feeds.
osquery lets you do SQL-like queries to find out about the system it’s running on (sharvil did a bunch of work on it, actually…)
terminal-notifier to pop up notifications from terminal/cron jobs.
tmux to have long-running terminal windows without having terminal windows open.
watch instead of “some command”+uparrow+enter+uparrow+enter+….
wget as shorthand for “curl http://xyz/tuv.json > tuv.json” (old habits…),
youtube-dl for downloading youtube videos.

streaks vs statistical streaks

Mon, 26 Sep 2016 00:00:00 +0000

Hacker News et al are obsessed with streaks, but I think they have some problems:

A single regression resets to zero.
There’s not an easy way to gradually ramp up your streak-commitment over time.

I prefer a different approach: statistical streaks.

Suppose I made a commitment to do something differently on 2016-08-26, and did it for the next 5 days; then my 30-day statistical streak avg = 0.166, but my 5-day statistical streak avg = 1.0.

pragmatic edc

Sun, 27 Dec 2015 00:00:00 +0000

Lots of folks wax poetic about their every day carry kit, and then include things like fishing hooks. That might make a “pragmatic hiking edc” kit, but I’m interested in some of the more realistic things that might happen:

Phone is dead and need to call someone (wife, parent, car insurance company, whatever) but don’t have the relevant phone number / insurance number / etc.
Minor illness like headache, indigestion, things like that.
Forgot my wallet at home and need lunch or cab fare.

purell sanitizing hand wipes pac-kit hydrocortisone pac-kit medication triage pack

life pro tip curb rampant consumerism by identifying actual needs

Sun, 23 Aug 2015 00:00:00 +0000

A while back, I realized that I wanted a nice digital SLR camera. Before I bought it, I made a list of all the things that I wanted to do with it. Ultimately, this ended up being a sort of self-justification for buying it, but it did serve one deeper purpose: I now had a list of about 20 things that I had committed to doing with my new camera. So while it didn’t actually prevent me from being rampantly consumerist, I did have a whole set of worthwhile things to do with my new camera!

debugging internet

Tue, 28 Oct 2014 00:00:00 +0000

My standard plan for debugging internet connections:

Can we reach stuff from some other device?

Usually, connection problems are something like “My iPad isn’t working,” which is caused by a flash of light in the sky, like when Swamp gas from a weather balloon gets trapped in a thermal pocket and reflects the light from Venus."

So try something other than your iPad on your WiFi to isolate whether it is a WiFi network problem or a “iPad"problem.

don't poll

Wed, 15 Oct 2014 00:00:00 +0000

A while ago, I wrote down a list of clever life rules in my day-to-day notebook. One of them was “don’t poll”. To say a bit more about it, don’t spent time waiting for things to finish and checking them constantly.

A more concrete example: I find myself running terminal commands that take ~5 minutes, and then wasting ~5 minutes watching them. This is pretty stupid. So what I have started doing instead is run something like

$ some_long_command
[ ... scroll scroll scroll ... ]
[ ... waiting for it to finish ... ]
[ ... give up ... ]
terminal-notifier -message "some_long_command done"
[ ... go do something else ... ]

Then, later I see a notification:

14 vs 1499 vs 15

Fri, 22 Aug 2014 00:00:00 +0000

Sometimes, it is tempting to see 14.99 and say “about 14,” even though we all know better. The problem with this is that by giving a 0.07% discount (14.99 vs 15), they have made you estimate a 7% discount (14 vs 15).

Nice trick!

launchd as cron crash course

Fri, 08 Aug 2014 00:00:00 +0000

insert

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Label</key>
        <string>com.whatever.five_after</string>
        <key>ProgramArguments</key>
        <array>
                <string>echo just ran > /tmp/whatever_five_after</string>
        </array>
        <key>StartCalendarInterval</key>
        <dict>
                <key>Minute</key><integer>5</integer>
        </dict>
</dict>
</plist>

into $HOME/Library/LaunchAgents/com.whatever.five_after.plist

If you call a script in the ProgramArguments section, remember to make it executable and define the script properly.

Run

launchctl load $HOME/Library/LaunchAgents/com.whatever.five_after.plist
launchctl start com.whatever.five_after

Can also run every N seconds with

<key>StartInterval</key><integer>N</integer>

Can also check the status with

some setup notes

Sun, 27 Oct 2013 00:00:00 +0000

zsh

Zsh is an amazing (mostly) drop-in replacement for bash.

On OSX, just run

> brew install zsh

You also want to install oh-my-zsh.

I went a little crazy with plugins. My list is:

plugins=(autojump brew git git-flow gnu-utils gpg2 osx textmate zsh-syntax-highlighting history-substring-search)

SSH

I ssh a lot. So I have a bunch of host entries in my .ssh/config file. Each looks like:

Host [shortname]
     Hostname [hostname]
     User     [username for hostname]
     IdentityFile [my home directory]/.ssh/[id_rsa file for this host]

You also need identity files for hosts you use. I tend to use a different one on each host I connect to; some might consider this overly paranoid. Probably it’d be better to use 1 key but only for a shorter period of time. In any case, you need to use

better matlab email notifications

Tue, 25 Jun 2013 00:00:00 +0000

One of my officemates asked me how I did my MATLAB email notifications. I had originally done it here. Of course, the machine we work on most didn’t support a mail or msmtp command, so I found an SMTP script, which worked okay, but frustratingly also required Python. On a bit more sleep, it finally occured to me that MATLAB might have an email script.

Turns out, it does. I wrote a little wrapper script around this to abstract out some of the email details.

Getting really fast at LaTeX

Wed, 10 Apr 2013 00:00:00 +0000

Taking LaTeX notes in real time is one of my favorite useless party tricks. I started developing my techniques during the last year or two of undergraduate work at University of Washington, and was extremely good at it by the end of coursework at Northwestern. There are several keys to taking LaTeX notes in real time:

Know LaTeX.
Shortcut appropriately.
Type keystrokes quickly.
One keystroke re-renders.
Type fewer keystrokes.
Type fewer “strange” keystrokes (backslashes, curly braces, etc)
Re-renders should scroll to your current location in the text.
Extremely rapid debugging of LaTeX expressions.

Before I get started, one other note: I mention TextMate a few places, but in principle there is no reason you couldn’t configure all the same things in Vim, Emacs, or Sublime Text. If I was starting over, I might use Sublime Text instead.

more stupid matlab tricks

Fri, 28 Sep 2012 00:00:00 +0000

I’ve been setting up long-ish runs on my MATLAB instance lately, which is nice because I can wanter off to do something else. The trouble is that I occasionally forget to come back or refocus on work again.

I’ve come up with two solutions to this:

The first is to use growlnotify to pop up a persistant growl message. This works well enough as long as I’m at the computer:

system('growlnotify -s -m "somefile is done"')

For more extended aways or if I’m going to take a nap while it runs, I might do something more like:

system('echo "matlab: uflX_aw_constr_log_5_15 done" | msmtp -a traviscj (mycell)@txt.att.net')

You need some setup before this works: I did a brew install msmtp and set up a .msmtprc file. After that, it should work goldenly, at least for AT&T customers. Others might need to look up their email/sms gateway number.

debugging matlab mex

Thu, 16 Aug 2012 00:00:00 +0000

One thing I’ve been doing a bit of lately is debugging MATLAB mex files; it seemed worth documenting. The broad strokes:

recompile all mex codes with ‘-g’
quit MATLAB
From a command prompt, run

$ /Applications/MATLAB_R2012a.app/bin/matlab -Dgdb
[snip]
(gdb) run -nojvm
>> run_your_mex_file

This gives debugging output. If there is an error in the code, you’re dropped back to a gdb prompt, where you can continue debugging in a semi-normal fashion. Typically, I end up doing a ‘where’ to get a stack trace, and debug from there more-or-less like usual.

Integrating Sparrow and Aperture/iPhoto

Fri, 13 Apr 2012 00:00:00 +0000

In my recent quest to take on digital photography, I’ve been using Apple’s Aperture to store download my pictures and do basic manipulation on them. It’s been working great, except that emailing is a pain because Apple hardcoded the email clients to:

Apple Mail.app
Eudora (really!?)
America Online(!?!)
Microsoft Entourage
Microsoft Outlook

while I’d prefer to use Sparrow, a lightweight client that Sharvil got me hooked on a while back. Rather than continue to use Mail.app to send pictures via email, I found out that Aperture actually uses some AppleScripts to do the actual sending of the email. That got me thinking: I just need to change the script to mail using Sparrow, instead of Mail.

fibonacci miles and kilometers

Thu, 29 Mar 2012 00:00:00 +0000

In my running, I have been trying to keep track in kilometers. This presents a couple problems: Somehow, my mind still thinks in miles, which is weird because I do not really have /that/ good of an idea exactly how far a mile is, either. Or someone wants to know how far a 5k is. Or, when I was running the 2011 Chicago Marathon, there would be kilometer postings between the mile markers. Anyway, it is handy to convert between them, but a bit of a pain.

Spaces setup

Tue, 25 May 2010 00:00:00 +0000

My workflow is probably pretty specific, but I figured I’d document it for people looking for ideas on how to set it up. This one seems to work pretty well for me.

. Terminal: for running stuff on my and other computers. . Textmate: writing mathematics, programming code, etc . Mathematica, MATLAB, and Papers . Mail and Adium . Firefox, Chrome, Safari . iTunes and VLC

I have this arranged in a 3×2 grid, such that Textmate is top center. From there I can navigate to terminal, math programs, and Firefox directly(control-{left,right,down}). It takes two navigations to get to communication programs and entertainment, which is good for concentration while working.

ZSH and scp/rsync globbing

Tue, 25 May 2010 00:00:00 +0000

I finally got annoyed at typing

tjohnson> scp tcj:*txt .
zsh: no matches found: tcj:*txt

I’d always fixed this by the up-CTRL-A-over-over-over-over-quote-CTRL-E-over-over-quote method, ie

tjohnson> scp "tcj:*txt" .

but the more proper and less annoying version is

tjohnson> scp tcj:\*txt .

However, in the spirit of inspired overkill, there are a couple other options. You can define some new aliases with

alias scp='noglob scp'

but that hardly counts as overkill, so instead I edited my .zshrc to include

My Hint for Foreign ATM Machines

Mon, 09 Feb 2009 00:00:00 +0000

I’ve been meaning to write this tip up for quite a while, but now that I’ve finally gotten some closure on it, I guess now would be a decent time. While I was in Brazil, there were two ATM machine clusters across the street from eachother, both between the beach and the hostel we were staying at. The CITIbank ATMs were more reliable, but the HSBC ATMs were a bit cheaper. At first, it always seemed worth the small extra, but since I never wanted to get much out at a time, I was racking up the bank charges. Also, several people had been using the HSBC ATM without issue, so I figured I would start using that one instead as well. This worked well the first couple of times, but one of the days I went in to get some cash out, it didn’t dispense. Undeterred, I went to one of the ATM machines someone else had just (successfully) used and tried there, and withdrew the money. This time it worked.

Minor OS X Shell Shortcomings

Sun, 19 Oct 2008 00:00:00 +0000

In spite of the fact that a lot of people seem to loathe the colorized ls functionality, I sortof grew up on it(so to speak). OS X, by default, does not have this functionality(well, at least, GNU’s –color option never works). I figured the quick and easy way to solve this was to install coreutils, but I found another option. It appears OSX included a version of ls that works with ls -G. The coreutils one is (by it’s virtue as a GNU tool) probably more feature-driven, but realiasing it as

Firefox PDF on OSX

Sun, 22 Jun 2008 00:00:00 +0000

June 3 was a fantastic day, though I didn’t know it at the time. The reason? My biggest bitch about Firefox has finally been fixed. The big problem is that Firefox’s OSX program has the default behavior of saving PDFs to Desktop and starting Preview with it. Which isn’t a huge problem, except that if you download the file several times, it just downloads a file with -N appended. This is sortof a pain because in college a lot of teachers call files hw5.pdf, which means that I pretty much have to go to the website each time, or look through about 5 files each time.

Protip on traviscj/blog

loan trickery

hype channels

more light, better pictures

watching progress in mysql

estimate ETA by including NOW()/UNIX_TIMESTAMP()

moar stupid jquery tricks

killing all timeouts in js

jquery selectors

guava RangeMap

everything has a failure rate

extracting the last few dollars from Visa/MC gift cards

things you don't learn in grad school

url encoding safe relational operators

_useful

.sqliterc

use the `locale.currency` library function

motorcycle learnings at 250 miles

Useful homebrew formula

streaks vs statistical streaks

pragmatic edc

life pro tip curb rampant consumerism by identifying actual needs

debugging internet

don't poll

14 vs 1499 vs 15

launchd as cron crash course

some setup notes

zsh

SSH

better matlab email notifications

Getting really fast at LaTeX

more stupid matlab tricks

debugging matlab mex

Integrating Sparrow and Aperture/iPhoto

fibonacci miles and kilometers

Spaces setup

ZSH and scp/rsync globbing

My Hint for Foreign ATM Machines

Minor OS X Shell Shortcomings

Firefox PDF on OSX

estimate ETA by including `NOW()`/`UNIX_TIMESTAMP()`