The Geek Stuff » Linux

Linux Time Command Examples

Himanshu Arora — Thu, 26 Jan 2012 06:02:45 +0000

There are times when you might want to profile your program on parameters like: Time taken by program in user mode Time taken by program in kernel mode Average memory usage by the program etc On Linux we have a utility ‘time’ that is designed specifically for this purpose. The utility ‘time’ takes a program [...]

How to Setup Rsyslog Remote Logging on Linux (Central Log Server)

Lakshmanan Ganapathy — Wed, 25 Jan 2012 06:02:43 +0000

Every Linux distribution have some kind of logging mechanism that records all the system activities. A while back we provided a list of 20 log files that are stored under /var/log that you might be helpful during troubleshooting. These logs are very critical for sysadmin for troubleshooting purpose. The following are the three common methods to log [...]

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TCP Attacks: TCP Sequence Number Prediction and TCP Reset Attacks

Himanshu Arora — Fri, 20 Jan 2012 06:02:55 +0000

Though TCP protocol is a connection oriented and reliable protocol but still there a various loopholes that can be exploited. These loop holes are mostly explained in terms of attacks. In the previous article on the TCP/IP Attacks series, we explained about ARP Cache Poisoning. This article explains the following two attacks: TCP sequence prediction [...]

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What is an IP Address? IPv4 and IPv6 Address Examples

Ramesh Natarajan — Wed, 18 Jan 2012 06:02:12 +0000

Question: I’ve been playing around with Linux desktop distro for a while. But, I’m very new to networking. Can you explain me in simple terms about what is an ip address and give me an example? Answer: When someone mails you a postal letter, you get it. How? Because it has an address that uniquely [...]

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Understand UNIX / Linux Inodes Basics with Examples

Himanshu Arora — Mon, 16 Jan 2012 06:02:38 +0000

Several countries provides a unique identification number (for example, social security number in the USA) to the people who live in that country. This makes it easier to identify an individual uniquely. This makes it easier to handle all the paper work necessary for an individual by various government agencies and financial institutions. Similar to the social security number, [...]

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TCP/IP Attacks – ARP Cache Poisoning Fundamentals Explained

Himanshu Arora — Fri, 13 Jan 2012 06:02:54 +0000

Suppose ‘A’ and ‘B’ are very good friends and ‘A’ shares all his secrets with ‘B’. Now if a guy ‘C’ comes in and fakes as if he is ‘B’. Can you imagine what could happen? Yes, ‘A’ could tell all his secrets to ‘C’ and ‘C’ could misuse it. In a layman’s language, this [...]

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Major Linux Vs UNIX Kernel Differences

Himanshu Arora — Mon, 09 Jan 2012 06:02:12 +0000

UNIX has been regarded as the mother of most of the operating systems. Some of the popular members of this family Include : System V Release 4(SVR4) developed by AT&T. 4.4 BSD From university of California AIX from IBM. HP-UX from Hewlett-Packard. Solaris from Sun Microsystems. Linux is relatively a new member of this family. [...]

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13 Basic Linux System Calls Explained using a Fun Linux Virus Program

Himanshu Arora — Fri, 06 Jan 2012 06:02:15 +0000

If you are interested in writing Linux system programming, you should learn all the basic library/system calls. This article has an example C program that covers a set of system calls that will help you understand the usage of these basic library calls. The example C code given below does the following: Automatically opens up [...]

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6 Linux Crontab Command Examples

Ramesh Natarajan — Wed, 14 Dec 2011 06:02:59 +0000

Crontab command manages the cron table that is used by the cron daemon to execute the cron jobs. This article explains the various command line options of the crontab command. 1. Tweaking Other Users Crontab using Option -u -u stands for user. This should be followed by a valid username in the system. -u option [...]

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Top 25 Best Linux Performance Monitoring and Debugging Tools

Ramesh Natarajan — Wed, 07 Dec 2011 06:02:33 +0000

I’ve compiled 25 performance monitoring and debugging tools that will be helpful when you are working on Linux environment. This list is not comprehensive or authoritative by any means. However this list has enough tools for you to play around and pick the one that is suitable your specific debugging and monitoring scenario. 1. SAR [...]

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