Tips I have learned on how to do things in shell scripts.
Fixtures are a great feature of PyTest but using them can be tricky. I found them to be very useful when all important environment logic resides in them and tests use a consistent interface without regard to how the environment is actually set up.
There are many options to install newer Python on CentOS, including building from source, installing from EPEL, installing from Software Collections (SCL), installing third party rpm package, etc. These all work to some degree of success. I had a different use case and could not find a pre-built rpm package to fit it.
My use case had these restraints:
- Install newer Python alongside the default system version
- Install multiple Python versions simultaneously
- Install the latest release from upstream Python project not just the latest release from a repository (repo)
- Do not build from source unless absolutely necessary
I configured requiring encryption in Apache Qpid (C++ broker) by adding the following line to /etc/qpid/qpidd.conf file and restarting the broker
Later when I used qpid-stat I got an error message
$ qpid-stat -q -b user@password/localhost:5672 Failed: AuthenticationFailure - Error in sasl_client_start (-4) SASL(-4): no mechanism available
After following a mailing list post to a JIRA to a Review Board entry I found that when broker requires a secure TLS connection then the connection string must use amqps protocol instead of amqp like so
$ qpid-stat -q -b amqps://user@password/localhost:5672
I was using version 0.34 of both broker and client.
An issue in FreeBSD 11-CURRENT - where make buildworld fails when run on RPi2 - prompted an investigation on automating the creation of bootable FreeBSD images from 11-CURRENT on a Mac OS X machine.
In an ideal situation, a build process can be kicked off at any time to produce an image that can be written to a Micro SD card for the RPi2 to boot from.
I found at one point that using an 8GB Micro SD card caused me headaches as I ran out of disk space at some points. I would recommend buying a bigger card.
This guide was created using OS X 10.10 (Yosemite) as the "client". All instructions assume:
- Correct software installed on OS X
- You know how to use Disk Utility and CLI
- You have already assembled the Raspberry Pi (RPi) hardware (case, etc.)
- WiFi USB adapter is not connected initially (it's configured later)
- Ethernet, HDMI, keyboard, mouse are connected to Raspberry Pi
- USB to TTL serial cable is available for use (I bought this one: http://www.amazon.com/gp/product/B00QT7LQ88)
- Drivers from http://prolificusa.com/pl-2303hx-drivers/
WARNING: This is a "living document" and will be updated as I learn from my mistakes. There may be a lot of errors in this doc so all the standard disclaimers apply.
In Atom open the command palette (Shift-Command-p) and enter command Install Shell Commands.
Configure Atom as git's editor.
git config --global core.editor "atom --new-window --wait"
Now when you do git commit it should open a new Atom window for you to enter your commit message.
One often hears about tight loops in the context of programming. I never really got what it meant. Until today.
A tight loop may be described as a loop that does very little work itself but has an impact on the performance of the larger program. For example, in an O(n) loop the faster it can execute each iteration the tighter it is.
In the Python interpreter whenever I hit enter it would show a blank line without a prompt and I'd have to press enter again to see the prompt. When I exited the interpreter the terminal would not show anything I typed. Pressing the return key would show my shell prompt on the same line. Up arrow or down arrow keys did not make any difference. reset was a last resort.
Python 3.4.3 (default, Aug 26 2015, 18:29:14) [GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.56)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> abs(1-0) >>> 1 >>> ^D>>> ~ $ ~ $ ~ $ reset