The difference between a regular text editor and the hex editor is that the regular editor represents the logical content of the file, while a hex editor represents the physical contents of the file. Hex editors are used for editing individual bytes of data and are mostly used by programmers or system administrators. Some of the most commonly used cases are debugging or reverse engineering binary communication protocols. Most of these mentioned hex editors are available to install from the default repository using your distribution’s package manager, like so: # yum install package Of course, there are many other things you can use hex editors – for example reviewing files with the unknown file format, performs hex comparison, reviewing program memory dump, and others. If no package available, head over to the website of each tool where you will get the standalone package for download and installation procedures, along with details on dependencies. Most (if not every) Linux distributions come with an editor that allows you to perform hexadecimal and binary manipulation. One of those tools is the command-line tool – xxd, which is most commonly used to make a hex dump of a given file or standard input. It can also convert a hex dump back to its original binary form. Hexedit is another hexadecimal command-line editor that might already be preinstalled on your OS. Hexedit shows both the hexadecimal and ASCII view of the file at the same time. The view of hexyl is split into three columns: Hexyl Hex EditorĪnother useful tool for examining binary file is hexyl, is a simple hex viewer for Linux terminal that uses a colored output to determine different categories of bytes.Offset column to tell you how many bytes into the file you are.Hex column, which contains the hexadecimal view of the file.(Note that there is a splitting line in between) This method can also be used to glitch some other formats as well, most notably BMP files.Īs with any glitch-by-corruption technique, too little has no effect, too much can destroy the file, but just enough results in glorious, glorious corruption.The installation of this hex viewer is different for different operating systems, so it is recommended to check the readme file in the project to see the exact installation instructions for your OS. Decreasing the quality of the JPG itself, which can be done with image editing software, can sometimes increase the likelihood of generating these artifacts through corruption. Making backup copies after every successful change will avoid heartaches when, not if, a misstep renders the image unviewable.Ĭorrupting JPG images often results in interesting patterns due to the corrupt data and the compression algorithms used, as seen enlarged in the example above. Now we can begin the process of making changes and checking the result in our favorite image viewer. Once we’ve identified the raw image data we can copy/paste chunks, search/replace sequences or just manually corrupt the data by changing the text (on the right side in the example) or the hex (on the left side in the example) of the raw data. Not to say that there’s no structure, it’s just harder to discern in compressed image data. We can see where some data ripe for glitching is in the above example where the file changes from structured, to seemingly random data. We need to locate the meat of the file, the raw image data, we can usually tell the raw data apart from the header and other important structural data by it’s garbled nature. The header contains information that is required for the image to be displayed at all and should be left intact (though feel free to experiment). The first bytes of a JPG file contain what’s know as the file header. Get started by making a copy of a JPG and open the copy in a hex editor - never edit the original file. You can see a JPG open in a hex editor in the image below. Most hex editors display both hex and text (also known as ASCII) in the same view but in separate columns. Editing the file using hex rather than text allows greater flexibility since we’re no longer restricted to text characters (which are each represented by two hex digits). Hex editors allow us to view and edit the bytes of a file using hexadecimal. If you don’t have a hex editor installed there are some freeware options list at the bottom of this post.
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