Monthly Archives: June 2013

All you wanted to understand about sudo vs su in Ubuntu Linux

Being a Linux admin user I have always used both sudo and su. As a system admin, it is very important for you to know the difference between two. For those who do not have basic idea about the difference between these two or are always confused between the two, here is a list of 13 Q&A that are aimed to make you understand the intricacies of  both sudo and su. Towards the end, I have linked some good discussion on web related to different options of sudo and su.

NOTE – This article is specific to Ubuntu only. Though some information might be applicable to most of the popular Linux distributions.
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Want Complete Linux Host Information? 5 Linux Commands That Can Do the Job

It is important for system as well as network administrators to be able to access all kind of system and as well as network related Linux host information. This information helps a great deal while debugging system level or network level problems. In this article, I will explain 5 commands (arch, dig, host, hostanme, uname) that will help you get most of host related information from system as well as network point of view.

NOTE- I have used Ubuntu 13.04 to run all the examples shown in this article
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Less Popular But Useful Linux Commands

Ever since from the age of unix to the present unix-like linux distributions, the linux world has added plethora commands to the kitty of linux users. At times it is just too difficult to keep in mind the complete set of available commands. However, we don’t even need to memorize all of them. It is sufficient to just be aware of commands and keep in mind the ones which are related to linux lives. Here I am consolidating a list of less popular but useful linux commands and how they work. I am sure, most of these commands would interest you and make your tasks simpler and efficient in some way.

NOTE – To read more about Linux command line tips, read our articles on Funny Linux commands and Interesting Linux command line tips and tricks.

 

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Ubuntu 13.04 – How To Get Rid Of “System Program Problem Detected” error

Its been a couple of weeks since I have been using Ubuntu 13.04. As far as the look & feel is concerned, its more or less same as Ubuntu 12.04 while with my daily work too I have not encountered something which has drastically changed. But there is something that started annoying me for past 3-4 days. The problem is that when ever I turn on my Ubuntu, a window saying System Program Problem Detected appears. It further says, Do You Want To Report The Problem Now?. I does not provide any way to get the details of the problem. You can either Cancel or Report Problem.

 

Here is a snapshot of the problem I am talking about :

rsz_system_prog_prob

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All You Wanted To Know About HERE Documents in Linux

HERE document is a special purpose code block through which text inputs can be supplied to programs on command line and within shell scripts. This way, HERE documents provide a good alternative for fetching inputs from text files.

In this article, we will understand most of the important aspects of HERE documents through some practical examples. Also, towards the end of article will be a list of resources which are worth read on various practical aspects of HERE documents.

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Linux Non Root Exploits – 4 Ways In which Even A Normal User Can Cause Real Damage To Your Linux System

Linux is considered to be a fairly secure operating system due to the way it is designed. For example, you cannot just download an executable and accidentally run it. If you want to execute it, you have to explicitly set its executable bit ON. Similarly, if you want to tweak any system specific parameter or configuration,  you have to attain root privileges first and after doing stuff, you can de-escalate the privilege level. These types of security pillars work well to ensure that Linux system doesn’t get exploited easily.

Most of the Linux users have this perception that as long as a hacker does not attain root privileges, there is not much damage that he/she can do to a Linux system. I would say it is true but to a certain extent only. And to prove my point, here, in this article, I will discuss 4 ways in which access to a Linux box even with non-root privileges can cause some serious damage.

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How I used eog utility to pull off a small Linux exploit

Back in 2012, after my article on Linux ELF Virus was published in Linux Journal, I was curious to come up with a trigger point for this virus. I mean what would compel a Linux user to execute it for the very first time? I thought about it many times but could not come up with something in a working state.

Cut to the present times – Last Friday, when I was coming back from my office through office bus, I was indulged in some technical talk with a guy who works on encoders and decoders for various media file formats. Suddenly the same thought struck in my mind and I asked him whether it is possible for him to come up with a situation where a Linux user clicks on an image file, the image gets displayed but a notorious code gets executed in the back end?
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