sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.locate.plist(you only have to do it once)
Before you do, edit /System/Library/LaunchDaemons/com.apple.locate.plist Get rid of the following portion so that it runs daily instead of just once a week though.
<key>Weekday</key>
<integer>6</integer>
Java 7 was released way back in 2011, but it's unfortunately not THAT uncommon for a large organization to get set in its ways (having found years ago, those battle-tested, magical, set of exact JVM tuning arguments that work for *their particular* application stack on a certain version of a 1.6 JVM) so that you don't get exposed to "newer" features. And to only get dragged kicking and screaming into JDK8 when Oracle deprecated certain versions.
So, what did Java 7 bring us? As developers, it seemed to be mostly about cleaning up syntax/getting rid of some of the boilerplate...
Connection conn = null;
try{
conn = getConnectionFromSomewhere();
// do work with the resource
} catch (Exception e){
// handle
} finally {
if (conn != null){
try {
conn.close();
} catch (Exception someOtherExceptionYouProbablyIgnore) {
// yah, you probably ignore this
}
}
}
Nope, now you can just do
try(Connection conn = getConnectionFromSomewhere();){
// do work with the resource
} catch (Exception e) {
// handle
}
You can also have your own objects work this way, look into java.lang.AutoClosable
} catch (IOException ex) {
logger.log(ex);
throw ex;
} catch (SQLException ex) {
logger.log(ex);
throw ex;
}
write this:
} catch (IOException|SQLException ex) {
logger.log(ex);
throw ex;
}
Map<String, List<Integer>> m = new HashMap<String, List<Integer>>();simplifying it slightly to:
Map<String, List<Integer>> m = new HashMap<>();(This seems slightly backwards to me, we're essentially specifying the details on the interface and waving our hands over the concrete implementation, instead of
Map<> m = new HashMap<String, List<Integer>>(); // does not workbut I'm not the designer - you must use the first version =)
Those are the big ones in my opinion. Did I miss any of your favorites?
tmux uses Ctrl-b as the default command prefix, that's ok on Windows but less than desirable on a MacBook Pro. Turns out that it's super easy to remap to something easier to type, but it's a two-step process.
First, let's get some usage out of the vestigial 'caps lock' key. Go to 'System Preferences' -> 'Keyboard' -> 'Modifier Keys' and then change caps lock to do something (marginally more) useful, the Control key.
Now that that's out of the way, remap the prefix in tmux by editing (or creating) your ~/.tmux.conf file. We only need one line in there to remap the prefix to Ctrl-a (which are handily right next to each other):
set -g prefix C-a
Two things to note: first, changing the caps lock key to be control affects ALL applications on your Mac, if you're like me and never use caps lock, that's probably ok - just something to remember. Secondly, sometimes you might want to be able to send Ctrl-a to an application that you're using inside tmux. If you think you will, just add another line to your ~/.tmux.conf file:
bind C-a send-prefix
This will allow you to send Ctrl-a to the application running inside tmux by pressing it TWICE.
[TLDR - Use a Docker container, install the 32-bit compiler chain and 32-bit dev libraries on the build machine, include the flags to enable CGO, set the target GOARCH, set ldflags to statically link]
So, originally I thought I'd be able to easily get my (trivial) Go app to cross-compile for the Edison (which is running a 32-bit linux variant) but I was quickly disabused of that notion. My app uses the `gopacket` library, which in turn uses C bindings (Cgo) to `libpcap-dev` to do the actual packet capture.
I had originally thought it was just a matter of adding "GOOS=linux GOARCH=386" to compile from my OSX box to target a 32-bit linux binary. It works fine for most apps, BUT it doesn't work for apps that are using Cgo. Ah, just forgot the "CGO_ENABLED=1" flag, right? Nope. That causes all sorts of different errors. Googling/Stack Overflow didn't really turn up anything helpful, but there's *probably* a way to do it. (there were a few projects out there, including gonative that seemed promising, but `gonative` only addresses Cgo-enabled versions of the stdlib packages, not if your project uses Cgo)
Rather than dig into the intricacies of cross-compiling on a Mac, I just pivoted to using a Docker container. I couldn't find an official Yocto linux container prebuilt, which is what the Edison runs, so I just went with a standard Ubuntu image.
root@ubuntu-docker-instance# go build listen.go
Sweet, compiled. All set, that was easy. Let's just check the binary to make sure all is good with the world.
root@ubuntu-docker-instance# file listen listen: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=11b30b279fd6580392e72bac70a5be034e12b2a7, not stripped
Oops, dynamically linked. Let's fix that by setting the correct ld flags, and check it again.
root@ubuntu-docker-instance# go build --ldflags '-extldflags "-static"' listen.go root@ubuntu-docker-instance# file listen listen: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.24, BuildID[sha1]=8a5a63b0151c2cef02399d091ea7339b2ca1d30b, not stripped
Ok, statically linked now but it's (still) 64-bit. The Edison is 32-bit, which means we'll have to fix that... should be cake, just use the "GOARCH" flag...
root@ubuntu-docker-instance/util# GOARCH=386 go build --ldflags '-extldflags "-static"' identify.go # command-line-arguments ./identify.go:19: undefined: pcap.FindAllDevs ./identify.go:23: undefined: pcap.OpenLive ./identify.go:23: undefined: pcap.BlockForever
What?! Oh, yes, need to tell the compiler about the Cgo code... (CGO_ENABLED=1)
root@ubuntu-docker-instance/util# GOARCH=386 CGO_ENABLED=1 go build --ldflags '-extldflags "-static"' identify.go
# runtime/cgo
In file included from /usr/include/errno.h:28:0,
from /usr/local/go/src/runtime/cgo/cgo.go:50:
/usr/include/features.h:374:25: fatal error: sys/cdefs.h: No such file or directory
# include
^
compilation terminated.
C'mon... now what? Some quick googling turns up the fact that you need the 32-bit gcc stuff, since the host architecture is 64-bit.
root@ubuntu-docker-instance/util# apt-get install libx32gcc-4.8-dev libc6-dev-i386 root@ubuntu-docker-instance/util# GOARCH=386 CGO_ENABLED=1 go build --ldflags '-extldflags "-static"' identify.go # github.com/google/gopacket/pcap /usr/bin/ld: cannot find -lpcap collect2: error: ld returned 1 exit status
Now what? Oh, although I have the 32-bit compiler chain, I DON'T have the 32-bit version of libpcap-dev. Let's fix that.
root@ubuntu-docker-instance/util# apt-get install libpcap-dev:i386 Reading package lists... Done Building dependency tree Reading state information... Done Package libpcap-dev:i386 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'libpcap-dev:i386' has no installation candidate
Huh? furious googling ensues... Ok, add the i386 architecture and try again...
root@ubuntu-docker-instance/util# sudo dpkg --add-architecture i386 root@ubuntu-docker-instance/util# sudo apt-get update root@ubuntu-docker-instance/util# apt-get install libpcap0.8-dev:i386
NOW we're cooking with fire. Let's give it one more try...
root@ubuntu-docker-instance/util# GOARCH=386 CGO_ENABLED=1 go build --ldflags '-extldflags "-static"' identify.go
Looks promising, it's a 32-bit statically compiled binary at this point. No obvious errors.
identify: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.24, not stripped
SCP the binary onto the Edison and test it...
root@edison:~# ./identify -inf=wlan0 2015/09/04 14:11:02 Starting up... 2015/09/04 14:11:03 Listening for ARP packets on en0 to identify dash button. Press the dash button and watch the screen. You will want the 'Source MAC' 2015/09/04 14:11:09 ARP packet, Source MAC[74:75:48:a4:59:a8], Destination MAC[ff:ff:ff:ff:ff:ff] 2015/09/04 14:11:24 ARP packet, Source MAC[74:75:48:29:a8:7c], Destination MAC[ff:ff:ff:ff:ff:ff]
SUCCESS!!!
Amazon is experimenting with wireless buttons (for $5 each) called Dash Buttons. The intended usage seem to be for Prime members to stick the button near a product that needs periodic refilling, e.g. laundry soap, so that when you're almost out of the product, you press the button and it (almost) magically reorders for you.
These buttons are nifty little pieces of technology, especially for $5. Someone has already figured out how to use them for something other their intended usage - read his post on Medium, it's very well written. He has source code in Python for accomplishing the hack.
I wanted to take a slightly different route to accomplishing the same type of thing. I have a bunch of hardware laying around that would be fun to play around with, including an Intel Edison board. I could write my code in Go, cross-compile it on my Mac, and just SCP it onto the Edison. Sounded like a fun evening or two, so that's what I did and threw it up on github.
Tested the code on OSX and it works. Attempted to compile it for Linux, so I can deploy it onto the Edison, and compilation fails...
$ GOOS=linux GOARCH=386 go build identify.go # command-line-arguments ./identify.go:19: undefined: pcap.FindAllDevs ./identify.go:23: undefined: pcap.OpenLive ./identify.go:23: undefined: pcap.BlockForever
I'm pretty sure it uses CGO and there are some details about cross-compiling that I'll need to figure out... but that will be for another post.
Error : .onLoad failed in loadNamespace() for 'rJava', details: call: dyn.load(file, DLLpath = DLLpath, ...) error: unable to load shared object '/usr/local/Cellar/r/3.2.0_1/R.framework/Versions/3.2/Resources/library/rJava/libs/rJava.so': dlopen(/usr/local/Cellar/r/3.2.0_1/R.framework/Versions/3.2/Resources/library/rJava/libs/rJava.so, 6): Library not loaded: @rpath/libjvm.dylib Referenced from: /usr/local/Cellar/r/3.2.0_1/R.framework/Versions/3.2/Resources/library/rJava/libs/rJava.so Reason: image not found Error: package or namespace load failed for ‘RWeka’
A workaround is to start RStudio from a terminal window by running the following line:
LD_LIBRARY_PATH=$(/usr/libexec/java_home)/jre/lib/server: open -a RStudio
"No Java runtime present, requesting install. ERROR: loading failed"
There are a ton of threads out there about this problem, but it seems to boil down to this unclosed (and untouched since 2014-01) JDK issue -> https://bugs.openjdk.java.net/browse/JDK-7131356
The "solution" can be found on the last comment on this rJava github issue: https://github.com/s-u/rJava/issues/37
I'm taking one of the Coursera courses right now on Reproducible Research and the first assignment requires you to build an Rmd file and convert it to html (using knitr). They do a really good job showing how to use RStudio to accomplish this task, but what if you don't want to bother with RStudio?
Here's (https://gist.github.com/slowteetoe/7b8426f567ac3df1d8f9) a simple bash script that watches an Rmd file. When you save that file, it runs knitr to convert it to markdown, and then converts the markdown to html and opens it in a browser... sorta a continuous integration for R markdown.
Couple caveats: you'll need to install the Ruby gem 'kicker', the r packages 'knitr' and 'markdown', and put this script somewhere in your path. It will also have to be made executable, 'chmod 755 knitr'. Also, it opens a different browser tab each time - but I couldn't figure out how to change this behavior and it was worth it (to me at least).
> g <- ddply(m, c("QGroup","Income.Group"), summarize, All = length(CountryCode))
Error: argument "by" is missing, with no default
> g <- ddply(m, c("QGroup","Income.Group"), summarise, All = length(CountryCode))
install.packages("jpeg")
I use homebrew, so I tried the usual...In file included from read.c:1: ./rjcommon.h:11:10: fatal error: 'jpeglib.h' file not found #include^
brew install jpeg Warning: jpeg-8d already installed brew unlink jpeg && brew link jpegBut that didn't fix the issue. The solution was to install the XCode command line tools with:
xcode-select --install(As a side note, this is my development machine so I already had XCode command line tools but for whatever reason I had to install them again, maybe an XCode upgrade?)
Invalid parameter: Message too long (Service: AmazonSNS; Status Code: 400; Error Code: InvalidParameter; Request ID: <redacted>)
{ id: 1234, status: "failure" }There's NO way that message will ever approach 256KB, so do I need to worry about truncating this message? No. Looking back on it, did I need a CountingOutputStream even with the truncating solution? Probably not, it was a JSON payload in UTF-8; UTF-8 handles the ASCII range in 1 byte per character so simply getting the length of the String should have been "close enough".
Always be the worst guy in every band you’re in. - so you can learn. The people around you affect your performance. Choose your crowd wisely.It is NOT a good idea to surround yourself with people who think identically or have had the same life experiences. Just because everyone around you hates node.js doesn't mean there aren't good ideas in it, but if there's no one championing it then it's easy to get mired in your (mis-)conceptions. Different viewpoints can challenge your perceptions and make you grow. Learn from their experiences and challenge dogma wherever you go.
In the almost 6 yrs I've been here, there's only been one person I've disliked working with; that's almost unheard of. It lends credence to the idea that hiring decisions based on culture can result in a better working environment. Unfortunately, niceness doesn't help you grow. There are people here I would love to work on projects with, but the reality is that there are no projects big or complex enough to justify us working together. Those people are a scarce resource that gets spread out to make the most use of their time - 1/5
I can't remember the last project that involved an actual technical challenge. A true craftsman doesn't blame their tools, but trying to build a skyscraper with a plastic hammer isn't a challenge, it's foolish. Most of the "challenges" here are self-inflicted. - 0/5
Zappos funds one conference a year and lets you expense work-related books. 'Pursue growth and learning' is actually a core value. There's a quarterly hackathon to explore and try to solve any problem you want. Ultimately though, it boils down to "Do I have somewhere to apply what I'm learning?" and the answer has been almost uniformly no. All the time and effort I invest in outside learning barely offsets the complete lack of mental stimulation offered from the projects available. - 2/5
You definitely have the freedom to play hard here, and the freedom to joust at windmills if you choose. But work hard? Not doing something that matters. 2/5
Wealth is the ability to fully experience life.Once I have enough to live the way I want, and to do the things I want, then it stops being a motivating factor.
I feel more than fairly compensated for this market, which is all I ask. - 5/5
And I go crazy cause here isn't where I wanna be
And satisfaction feels like a distant memory
Should I stay or should I go now?I normally stay away from blogging about career advice, or advice in general, but sometimes you get thrown a curveball - something like "The Offer" and have to come up with a way of dealing with it.
If I go, there will be trouble
And if I stay it will be double
- The Clash