Unix Operating System Tutorials

UNIX operating system articles, tutorials and resources
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1. What Is Kernel? A kernel is a central component of an operating system. It acts as an interface between the user applications and the hardware. The sole aim of the kernel is to manage the communication between the software (user level applications) and the hardware (CPU, disk memory etc). The...
Netcat (also known as ‘nc’ or ‘Swiss Army knife’) is a networking utility used for reading or writing from TCP and UDP sockets using an easy interface. NetCat is designed as a Dependable ‘back-end’ device that can be used directly or easily driven by other programs and scripts. Netcat is a treat to...
Introduction Many times we write programs which runs many instances of itself, either while using fork or we manually run many copies of the same program, so during the development stage we may need to kill all running instances and modify the program and re-run, or there may be other situations...
SSH is a abbreviation for Secure Shell is a network protocol that allows data-exchange between devices on the network..This is mainly used in linux OS's to access shell accounts , shell commands etc... SSH was mainly designed as a replacement modification to telnet etc..other insecure remote shells...
lsof or LiS Open Files is a very powerful command available on most of Unix-like systems, it lists all open files (in *nix everything is a file, drives, sockets, inodes, etc.). The listing can filtered using various parameters like process id, owner of the process, etc. In this article we'll...
Now let us try to do same in Unix as we have discussed in the following Article - Splitting String Using Delimiter in Oracle In Unix it is pretty simple. We can use below commands to split echo "GO 4 EXPERT|99999|20130101|20131231"|cut -f1 -d"|" or echo "GO 4...
Introduction WINE (Wine Is Not an Emulator) is a free software application that aims to allow Unix-like computer operating systems to execute programs written for Microsoft Windows. Wine also provides a software library known as Winelib against which developers can compile Windows applications...
This article will give people with no previous UNIX experience some sense of what UNIX is. This article will cover the history of UNIX and an introduction to UNIX. HISTORY OF UNIX AND CAUSES FOR ITS POPULARITY Most discussions of UNIX begin with the history of UNIX without explaining why...
tee command is common on Unix like systems and on Windows PowerShell. The tee command writes the input to the file specified and also to the standard output, it was named after the plumbing T-splitter used. Here's a graphical presentation of the tee command: ...
Sometimes you must have noticed that you have 1gb of data to write. But you are unable to decide that what media should you use. Because 1 DVD can be more than enough required and 1 CD is not enough for writing the data. And if you use another CD, that would be probably half free. So, you will be...
I have been using linux for 2 years now, and I can tell you that I learn something new virtually every day. And a few of those things I have learned are very rare to be seen all the time. Here are a few of them. If you are using Redhat's netcfg utility to connect to the internet and you are sick...
Command line skills are something you pick up over time. When something needs to be done, you work out how, and from then on you know how to do it. Few take the time to systematically learn the ins and outs of the tools at their disposal, however, and so may not be aware of all the possibilities of...
Concept: The UNIX kernel can keep track of many processes at once, dividing its time between the jobs submitted to it. Each process submitted to the kernel is given a unique process ID. Single-tasking operating systems, like DOS, or the Macintosh System, can only perform one job at a time. A...
APTonCD is a tool with a graphical interface which allows you to create one or more CDs or DVDs (you choose the type of media) with all of the packages you've downloaded via APT-GET or APTITUDE, creating a removable repository that you can use on other computers.One thing you need to remember this...
This is continuation of my previous articles .. Please don't miss them :- Bash Simple Tricks Bash Simple Tricks (continuation) Again I am following a question – solution approach to demonstrate my scripts.. Scripts
In this tutorial of mine I am demonstrating some bash commands with some example scenarios/questions and their solutions.... What is Bash:- Bash or Bourne Again Shell is a reimplementation of Bourne shell... Bash is the default shell that comes with most of the linux distributions out...
Normally web traffic (HTTP) is unencrypted i.e. it's passed around the network in plain text, so anyone with the right tools can view what's being transmitted. This is okay generally, but when we pass sensitive information like credit card information, passwords, nowadays even personal information...
Most sys admins know the importance of keeping an action log where various tasks, configuration changes, etc. are kept. Simple logs indicating, "I did this" or "John did that" may be sufficient in some organizations, but for some, full transcripts of changes made are desired. Doing a copy-and-paste...
You might have studied various mechanisms through which two processes interact on same host. For example message queues, shared memory etc. But what about interaction between two process running on two different hosts (lets say on a LAN or WAN). Here comes the concept of network programming where...
Shell Tips & Tricks Create A Command Alias Most of us use 'ls -l' so, will it not be easier to have a smaller command to show us long listing, add the following line to ~/.bashrc alias ll='ls -l' Using it # ll