Month: December 2013

Link: Internet Connection Down? Get a Voice Alert When Your Mac is Back Online

We’re all incredibly reliant on our internet connections these days, but sometimes those connections aren’t so reliable. Whether it’s due to an ISP failure, a router being down, someone tripping over a cord somewhere, or whatever other occurrence, it can be frustrating to wait for a downed internet connection to come alive again. We’ve all known users who simply hit the “refresh” button on a web browser repeatedly to see when things revive, but there is a better way. Users who are comfortable with the command line can use a better solution, which utilizes the ping tool to detect an active internet connection and the text-to-speech say command to verbally announce when things are live again. Be sure to have the volume turned up on the Mac to use this.

It should be noted that with only slight modification you could use this same technique to monitor a specific site that is down, and notify you when it comes back up. The article and reader comments also show how to receive other types of notifications, in case you are in a situation where you can’t hear a voice alert, or it would be unappreciated by others nearby.

Full article here:
Internet Connection Down? Get a Voice Alert When Your Mac is Back Online (OS X Daily)

Link: How to Change the Date of your Digital Photographs

John Q. Public has just finished importing the videos and pictures from the digital camera to his laptop but realizes that the media files are incorrectly time-stamped.

Maybe the date and time settings of his “point and shoot” camera were set incorrectly or maybe the digital camera was stamping the files with local time though the pictures were being shot in another country with a different time zone. He probably forgot to change the time stamp of the camera before going on vacation.

How does John change the data and time of his pictures?

Full article here:
How to Change the Date of your Digital Photographs (Digital Inspiration)

Ubuntu Doesn’t TRIM SSDs By Default: Why Not and How To Enable It Yourself

Ubuntu wants to enable TRIM for SSDs by default in Ubuntu 14.04. In other words, Ubuntu isn’t already using TRIM, so your SSD is slowing down over time. But why isn’t Ubuntu already using TRIM?

This news will likely come as a surprise to many people, who assumed that Ubuntu and other Linux distributions were already using TRIM. TRIM prevents SSDs from slowing down over time and is a necessary part of SSD maintenance.

Full article here:
Ubuntu Doesn’t TRIM SSDs By Default: Why Not and How To Enable It Yourself (How-To Geek)

Links: Raspberry Pi / Linux security series

While this series is intended specifically for Raspberry Pi users, anyone new to Linux that would like to know how to secure their system would likely benefit from reading these articles from “The Unwritten Words”:
Raspberry Pi: Initial Setup (Security – Part I)
Raspberry Pi: iptables (Security – Part II)
Raspberry Pi: fail2ban (Security – Part III)

Link: Linux Routing Subnets Tips and Tricks

Does anyone do any serious disconnected computing? I daresay not. We install and update our Linuxes over the Internet, and install new software, and look up information online. Networking is essential to a Linux system, and has always been integral even as our favorite glossy proprietary operating systems couldn’t network their ways out of paper bags. I like to think of IPC– inter-process communication– as a form of internal networking between processes, though wiser network gurus may disagree.

Networking in Linux is easier than it used to be in the olden days. Why, I haven’t customized a kernel in dog’s years, which was something we had to do a fair bit back in the days of walking uphill both ways in the snow. But it’s not quite pure magic yet and we still need to know a few things. Let’s start with routing between subnets. Dividing even a small network into subnets is a useful management tool for security, and for allocating resources such as file and printer shares and Internet access. You can isolate your subnets from each other, or allow them to talk to each other.

Full article here:
Linux Routing Subnets Tips and Tricks (Linux.com)

Link: How to Bake an Onion Pi (Tor proxy on Raspberry Pi)

Feel like someone is snooping on you? Browse the web anonymously anywhere you go with the Onion Pi Tor proxy. This is a cool weekend project that uses a Raspberry Pi mini computer, USB wi-fi adapter, and Ethernet cable to create a small, low-power, and portable privacy Pi.

Full article here:
How to Bake an Onion Pi (Make)

Link: Alternative way to flash your Raspberry Pi OS

Did you ever want to flash your root partition straight to USB stick/HDD/SDD instead of first dd-ing it onto SD Card and then coping it again onto another media?

I got bored of the double work that is provided by RPi geeks. Yeah, it’s fine if you’re a total beginner (though one might get lost pretty easily) and want to use only the SD Card. But what if you know how to deal with Raspberry Pi already and perform the card setup mechanically, coping the root partition to a USB stick before you run the system? There is an easy way to do it, less time consuming and faster. It involves using loop-mounting partitions from a disk image.

Full article here:
Alternative way to flash your Raspberry Pi OS (The Unwritten Words)

Link: Understanding Pipes and Redirection For the Linux Command Line

Two powerful features of the Linux command line shell are redirection and pipes which allow the output (or even input) of a program to be sent to a file or another program. You may have already used this features without being aware of it. Whenever you have used the “>” sign in a command or “|” then you have used redirection or a pipe, respectively.

Full article here:
Understanding Pipes and Redirection For the Linux Command Line (Make Tech Easier)

Link: Raspberry Pi Watchdog Timer

Soon I’m going for holidays and leave my Pi on its own. Thus, I made some precautions in case it froze (though after almost a month with it, I never had such a problem, but never say never). I’ve found a great tool, that would reboot my machine after it suddenly froze for any reason. This would soothe my nerves in case I wasn’t able to access my device and was wondering what might have happened (I’m not afraid the power might fail; not unless there was a nuclear war or a nasty sun burst that would destroy all electrical equipment – than we would be doomed and there would be no reason to worry about a small Pi).

…..

A watchdog timer is commonly found on embedded systems and is used to detect when the system is hung up on a task. Watchdog timer is basically a countdown timer counting  from some initial value down to zero. When zero is reached, the watchdog understands that the system has hung up and resets it automatically.

Thankfully, the Raspberry Pi’s BCM2835 SoC has a hardware-based watchdog timer on board. It is specially useful if you have a Raspberry Pi in a remote location (or a headless Pi) and the operating system hangs and there’s no one around to reboot it. How to enable the watchdog timer?

Full article here:
Raspberry Pi Watchdog Timer (The Unwritten Words)