Understanding the Rsync Utility

We’ve all had a file scare sometime in our computing careers. In many cases, the computer won’t show any signs of corruption until everything starts to fail at once. When things do go wrong, your first thought is always about the safety of your files – will you be able to recover them?

If you had backed up your files regularly with a backup utility, you wouldn’t have to worry about whether you would be able to recover all of your data. However, many people do not see the value in doing regular backups, because they think that it is a waste of time. Their rationale is that the probability that a computer will need to access the backup is small enough that waiting for the computer to copy over all of their files every time they do a backup is pointless.

Rsync is an intelligent backup utility. Instead of duplicating the entirety of the data which is being copied over (looking at you cp), rsync will calculate the differences between what is being copied and what already resides in the directory, and will only copy over the differences. If the creation time and size of a file have not changed, rsync will move on without making any copies. This saves lots of time, which would have been spent on doing costly I/O operations. Rsync will take about as long as cp to complete the first time a backup is made, but subsequent backups could be done in a matter of minutes instead of hours, depending on the frequency with which you back up your system.

Rsync also includes a lot of flags which can help with the backup process.

–exclude is useful for ignoring large directories. If a full linux backup is being made, directories like /var and /proc will be excluded due to their huge size and session-specific information.

–delete will remove anything which is present in the backup directory which is not present in the source directory. This is mostly useful for creating snapshot copies of a system. If you would rather keep every file backed up, even if you delete it on your own system, this flag is not necessary.

–archive, also known as -a, is another useful flag. It is equivalent to the flags -rlptgoD. It performs a snapshot archival of the specified system. I’ll go into the individual flags in more detail below.

  • The -r flag stands for recursion. It tells the program that you want it to copy the contents of a directory as well as its shell. If this flag is not set, you will have an unhappy TA on your hands, looking at a series of empty directories.
  • The -lptgo flags preserve the information on a certain file. If these are not set, new creation information is created for each newly generated file, indicating the permissions, owner, etc. of the directory where the copied information is going to be stored. To keep the creation information on the original file intact, -l preserves links between files, -p preserves the permission of the file, -t preserves the creation time of the file, -g preserves the group the file is associated with, and -o preserves the owner of the file.
  • The -D flag is the most optional of all of the backup information. It preserves information on the devices and any special files which are mounted at the time of the backup.

Finally, rsync has flags which let the user know what is going on during the backup process. The -v flag stands for verbose. It outputs the current step on the screen, so the usre will know how far into the backup they currently are. Since this is an I/O operation, it will slow down the overall program, but many people believe that this kind of knowledge is worth the tradeoff. In order to further modify the -v flag, you are also able to set the -h (human-readable) flag, which makes any sizes that the computer outputs be rendered as MB and GB, as opposed to full byte numbers.

This is an example of an rsync script command, which will take a snapshot of whatever is in folder 1 and store it in folder 2, deleting anything in folder 2 which is not in folder 1 and telling you everything that it is working on in between:

rsync -av –delete /home/folder1/ /home/folder2/

 

Stream services for TV and Movies

From cable-cutters to college students, nearly everybody is interested in video streaming services. You may be tempted to use torrenting software to get your TV shows and movies, but this software is notorious for landing people with copyright violation notices and occasionally some hefty fines. There are many legal alternatives to torrenting software, and I will discuss them here. Continue reading

Getting Started with ZSH

If you’ve ever used a system shell before (the Terminal application on Mac’s and most Linux OS’s), you know how powerful they can be. If you haven’t, the system shell (also called the command line), is basically another method of controlling a computer. Just as you normally open programs, edit documents and manage files, the same can be done in a shell. However, all will be done using only text called commands. The simplicity and elegance of the shell is why it’s loved by many.

Bash

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Zotero Citation Software

Have you had trouble finding a good site to help you create a bibliography? Tired of hunting down pieces of information about your source? Or maybe you’re not sure if you have enough information in your citations. Now there is an answer to all of your questions and that answer is Zotero. Zotero creates citations for you at the click of a button! It allows you to store your citations in folders or libraries for organization and upon registering with an email and password(for free) you can access your citations across multiple devices! Continue reading

How To: Mount UDrive in Ubuntu


You may have noticed that the Help Center provides instructions for making your UDrive easily accessible on your desktop PC and Mac on our website, but, what if you’re running a Linux distrubution? Not to worry! By taking the following steps, you’ll soon be able to back up and shuffle around your important files with ease. Below are instructions for setting up your UDrive with Ubuntu 12.04 LTS. While following the steps, click on images to enlarge for details. It takes a few Terminal commands, but you’re already using Linux, right? You’re not afraid of those!

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Configuring Exchange Email and Calendar in Thunderbird

Configuring Email clients can be a frustrating task due to the sheer number of different server settings that need to be properly entered in order for it to work properly and the variety of choices in desktop mail clients. Fortunately, this guide is written specifically for configuring UMass Amherst Exchange mail and calendaring for Thunderbird, an open source desktop mail client that is compatible with most Windows, OS X, and Linux distributions. For your convenience, the instructions and screenshots in this guide should exactly match what you see on your screen.

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Ubuntu: Linux for Human Beings

Tux

Nothing has more impact on how you use your computer than your operating system. Most users are familiar with Windows, which is by far the most popular (with over 90% of the population using it, according to Net Applications in 2014), and Macintosh OSX, which occupies about 7.5% of the remaining market share. The remaining share goes to an operating system called Linux, which is different from the other two in a few key ways.

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Virtual Machines: Running Another Operating System On Your Computer the Easy Way

Virtual machines are programs that allow you to run programs (or an entire operating system) on your computer that weren’t originally designed for it. Most commonly this is done by Mac users who want to run Windows programs which don’t have versions for Mac OSX, but can be done with almost any operating system (like Linux). If you want to run Mac OSX you have to be on a Mac computer (unless you have some tech skill), but otherwise you’re free to experiment. All you have to do is download the operating system .iso or .dmg file or buy an installation DVD and you can use that to start up your virtual copy of that Operating System (OS).

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Understanding SteamOS

steamcroppedOn September 20th, users of the popular videogame distribution platform Steam were greeted with the news that Valve Corporation would be releasing a new operating system; SteamOS. This had been foreshadowed by Valve’s Gabe Newell at LinuxCon the week before, but the news still came as a pleasant surprise for both PC and console gamers alike.

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Turkeybytes: Vim Text Editor

This Thanksgiving, I am thankful for Vim. Vim, which stands for “Vi Improved,” is a text editor that is based on Vi, an older editor that was used with the original Unix operating system. Vim is free, open source software that comes with most modern Linux distributions. It is mostly for writing programs and scripts, but can be used to edit any sort of basic text file. It is designed so that the user never has to take their hands off of the keyboard or touch a mouse. If you use Vim properly, your palms can stay in the same position while only your fingers move. For this reason, Vim users are occasionally referred to as keyboard cowboys.

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Turkeybytes: UNetbootin

With the release of Windows 8.1 I finally decided that it was worth replacing the trusted Windows 7 with Microsoft’s latest and greatest. Windows 8 is awesome; it provides many behind the scenes system improvements that will make your PC run more fluidly, and with Windows 8.1 Microsoft has fixed many of the user interface flaws that users and critics have been complaining about. I highly recommend upgrading to Windows 8.1 if you are a UMass student, faculty or staff because it is FREE through Microsoft Dreamspark!
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Turkeybytes: Elementary OS

This week I’m thankful for Elementary OS!

Elementary OS is an open source Linux distribution that’s sure to hit home with anyone who loves minimalism and simplicity. With all the functionality of Ubuntu 13.04 and some design ideas similar to OSX, Elementary OS is lightweight and compatible with most Apple computers and PCs.

Elementary OS

The newest release, called Luna, is easy to use and free to download. Just like any other Linux distribution, Luna is highly customizable. Want to swap out your dock for something more OS 10.9-esque? No problem. You also already have all the functionality you need – there’s a software store, system settings, and some preloaded programs. If you’re comfortable with Ubuntu, you’ll have no problems navigating this interface.

Check out this site for more information, and to download Elementary OS for free. If you want a physical DVD sent to you instead, you can buy one at the store for $10.00.

Terminal Basics

In OS X or Linux, you can do a lot with Terminal. This is where you can enter in commands, and your computer will execute them. You can do anything from basic file management, to running programs, to even playing games. But in order to do all that, you have to start with the basics. Here are a few commands you’ll need to get a grip on first. Continue reading

Who knew Linux had games?

If you’ve recently switched to Linux or are just looking for some new native Linux games to play, you may find yourself at a loss. Luckily, there are some excellent sources for native Linux game reviews. Websites such as linuxgamecast.com or thelinuxgamer’s Tumblr are excellent sources of great reviews for Linux games which you might not know exist and some that you do, but didn’t know you could play on Linux. Continue reading