Wednesday, October 31, 2012

Flowing Fix: Clear your printer queue on Mac OS X

via: http://forums.techguy.org/apple-mac/1062988-solved-canon-ip6700d-printer-wont.html#

If you are having trouble deleted a file from your printer queue, you might have to resort to a terminal line command.

1) Open up "terminal" by searching for it with Spotlight or going to "/Applications/Utilities/Terminal"
2) then, at the prompt type the following:
    lprm -
3) This should remove it from the queue.  If not, you can reset the print system.

If step 2 above did not work: To reset the print system, go to the printer system preference dialog, right click your printer and choose reset print system. After which you will have to re-add your printer.

Wednesday, October 24, 2012

Batch operations on images: IrfanView

Previously I covered batch operations from the command line.  IrfanView is a small and fast program for viewing images, but it also has a batch conversion tool that can convert between image types (e.g. TIFF to JPG):


In it's advanced mode, it can crop, resize, and do many other operations:



Get it here: http://www.irfanview.com/.  You'll also want to download the plugins installer to get access to more file types.

Wednesday, October 17, 2012

Batch operations on images: ImageMagick

Having to do the same operation on multiple images sometimes lends itself to batch processing.  There are several tools for doing this.  I'll briefly introduce you to one tool: ImageMagick.  ImageMagick is suite of command-line programs that allow you to resize, crop, convert, and do many other useful things.

To use ImageMagick, download and install the program.  (Note that during the installation you will need to add the tools to the path.)  If you want to do operations on PDF, postscript or EPS files, you will also need Ghostscript.  Open a command prompt in Windows.

I'll demonstrate how to create thumbnails from the first page of a PDF file:
convert -thumbnail x100 "File.pdf[0]" File.thumb.png
This creates a thumbnail File.thumb.png from the first page of the file File.pdf[0] instructs convert to use the first page.  If you leave off the [0] part thumbnails will be created for every page in the PDF.  The thumbnail height is 100 pixels, and the width is automatically determined.

If you want to automate this, you can use command line batch processing, MATLAB, or my favorite scripting language, Perl:
foreach my $file (glob("$ARGV[0]/*.pdf"))
{
   print "Converting $file\n";
   print `convert -thumbnail 133x100 "${file}[0]" ${file}.png`;
}

Wednesday, October 10, 2012

Linux Live CD for increased banking security

Many people don't realize how easy it is for criminals to siphon money from your bank account.  The basic procedure is 1) install a virus on a target computer, 2) virus grabs passwords and/or credit card numbers from the target computer, 3) send stolen information to criminal hacker, and 4) money is used to purchase items or to transfer out of the country via money mule.  The RSA security firm has discovered that criminal gangs are working in concert to attack U.S. banksSophisticated techniques can be used to ensure that the criminals receive the money.  Many times it can be impossible to detect that you have one of these money-stealing viruses.

Enter Linux Live CDs.

In order to ensure that your banking information is safe, you can use a Linux Live CD to temporarily boot into Linux, use a web browser to perform online transactions, and then boot back into Windows.  If your Windows computer has password-stealing malware on it, that malware will have no knowledge of your banking transactions.

The U.S. Air Force has developed a Live CD directly for this purpose: Lightweight Portable Security (LPS) that can also be installed on a USB flash drive.  This particular Live CD has a GUI that looks similar to the Windows interface, making it familiar and easy to use.

If LPS doesn't work for you, try Puppy Linux or Ubuntu.  Many more are available to choose from, too; see http://www.livecdlist.com/.