Linux Blog

Impressed with the PostgreSQL Installer

Filed under: General Linux,Linux Software — TheLinuxBlog.com at 10:48 am on Monday, April 27, 2009

Until today I had never installed PostgreSQL from the Binary provided at postgresql.org since it’s pretty much always in some form of repository provided by most distributions. Today, for the first time ever I installed it and have to say I’m very impressed with the installer. I some what shuddered as I saw a “install shield” type installer interface, as my past encounters with these have generally tended to not work out so well. What I noticed about the PostgreSQL installer though was different from the “install shield”, it was BitRock. BitRock is a cross platform installer for “Windows, Linux, OS X and more…” as this was my first experience with BitRock with a Linux machine I have to say it was a positive one. It allowed me to install PostgreSQL with some custom components pretty effortlessly. While most won’t need to do a custom installation as PostgreSQL will probably be in a repository, its handy to know that the installer works.

BitRock does not appear to have a completely free license but they do seem to give open source projects a “free copy.” Not sure how I feel about this, but I guess if they’re out to make money then it could work for them. Apparentely it doesn’t take much to please me on a mundane Monday morning, I’d have been perfectly fine with a tarball and manual configuration but the GUI has brightened up my day. Thanks BitRock! Does any one else have any encounters or shocking experience with installers? What about BitRock in general?

Command Line Image Editing with ImageMagick

Filed under: Linux Software — TheLinuxBlog.com at 1:52 pm on Friday, February 13, 2009

Image Magick

Image editing is often considered a pitfall of the Linux desktop. When I was in school a number of years ago a Windows user (that later converted to the hipster OS X “better than thou” type) said to me:
“I don’t know why any one uses the command line anymore, it’s obsolete”
People often forget about the power of the command line. The command line may not be the best utility for everything but image editing is a shining example of how it can be used. I wouldn’t recommend trying to type a command that touches up your photos, but any operation that has to be repeated a number of times can be easily accomplished through a series of commands.

While there are many command line image editing tools available, this post focuses on the ImageMagick suite. While all of this can be read in the man page I aim to simplify and document for both myself and other casual ImageMagick users. By far the most valuable resource for ImageMagick is the online documentation.

Basically ImageMagick takes a number of parameters depending on the function you are to perform. Most commonly an input filename, an operation and an output filename. You can specify the same filename for both input and output in most cases, unless you are trying to keep the source image in its original form.

Here are some of my favourite and most used functions of imagemagick:

Resize an image
To resize an imagemagick is very simple. Using convert you specify the -resize option. You have several options when resizing, resize by width or height. You can also resize while adding a background color if your image has strange dimensions

Rotate an Image
Rotating an image is a snap, using convert with the source file -rotate <degrees> out file you can rotate by any number of degrees. 90, 180, 270 are most common, to change orientation but other angles may be used. Keep in mind that you may want to set a background color to do this.

Flipping an image
There are two ways to flip and image and they get sort of confusing. Imagemagick uses -flip for vertical images and -flop for horizontal flipping.

Quality
Adjusting the quality of an image is sometimes desirable for saving files to the web. Use -quality <0-100> (100 being the best) to adjust the quality

Working with GIFS
Gif’s can be edited or created by those patient enough to do so. The major think about working with gifs is the -coalese option. This takes each frame from the gif and makes it its own image. Be careful when using this as it will make Filename.gif Filename-1.gif, Filename-2.gif, Filename-3.gif and overwrite those files if they already exist. You can then work on each frame individually, or with a script and then join them back together.