How to plot a bar graph on Gnuplot

Question: How can I create a bar graph (bar chart) using Gnuplot? A bar graph is a plot which visualizes data values using proportional-size bars. Bar charts are useful when you want to compare multiple items among different categories. As you can imagine, they are much more effective than a table of numerical data. This […]
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How to compress JPEG images from the command line on Linux

Question: I have several JPEG photo images I have taken using a digital camera. I would like to optimize and compress the JPEG pictures before uploading them to Dropbox. What is the easiest way to compress JPEG images without losing their quality on Linux? Image resolution of today’s picture taking gadgets (e.g., smartphones, digital cameras) […]
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How to install a USB webcam in Raspberry Pi

Question: Can I use a standard USB-based webcam on Raspberry Pi? How can I check if my USB webcam is compatible with Raspberry Pi, and how can I install it on Raspberry Pi? If you want to take pictures or record videos using Raspberry Pi board, you can install Raspberry Pi camera board. If you […]
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How to crop an image from the command line on Linux

Question: I would like to get rid of white margins of an image file. Is there an easy way to crop an image file from the command line on Linux? When it comes to converting or editing images files on Linux, ImageMagick is undoubtedly one of the best known all-in-one image software. It boasts of […]
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How to rotate x-axis labels on Gnuplot

Question: I want to rotate the x-axis (xtics) labels in a Gnuplot figure. What is the Gnuplot command to rotate x-axis labels? When you plot many bars along with their labels across x-axis, rotating labels on x-axis helps save space. To rotate x-axis labels on Gnuplot, you can use the following command. set xtics rotate […]
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How to change GIMP default settings permanently

Question: I use GIMP image editor regularly. I would like to customize its default settings to my liking, so that I don’t have to change GIMP settings every time I launch it. How can I change the default settings of GIMP permanently? First, go ahead and customize the default settings of GIMP as you wish, […]
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How to draw stacked histogram on Gnuplot

Question: How can I draw a stacked histogram (stacked bar chart) using Gnuplot? In a stacked bar chart, data is visualized with items stacked on top of one another or side-by-side, and different items are differentiated by colors or patterns. Stacked histograms are useful when the sum of item values is as important as the […]
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How to install digiKam on Linux

Question: How do I install digiKam photo management software on [insert your Linux distro]? digiKam is an open-source digital photo management software for the KDE desktop. It can runs on most of other Linux desktops as long as required libraries are installed. digiKam allows users to manage and preview digital photo albums, as well as […]
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How to install ImageMagick on Linux

Question: How can I install ImageMagick on [insert your Linux distro]? ImageMagick is a suite of command line utilities for image conversion and editing. As one of the most popular image editing software suite, ImageMagick can support almost all kinds of raster image types including GIF, JPEG, PDF, PNG, Postscript, SVG, and TIFF. Install ImageMagick […]
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