Articles by Himanshu Arora
About Himanshu Arora
Himanshu Arora has been working on Linux since 2007. He carries professional experience in system level programming, networking protocols, and command line. In addition to HowtoForge, Himanshu's work has also been featured in some of world's other leading publications including Computerworld, IBM DeveloperWorks, and Linux Journal.
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Linux fgrep Command Tutorial for Beginners (with Examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 1 While grep is a well-known Linux command (we've already covered it in detail), do you know that there exist two different variants of this tool? Yes, these are egrep and fgrep. In this tutorial, we will discuss the latter (fgrep) using easy to understand examples.
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Linux expr command tutorial for beginners (with examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 1 Sometimes, while working on the command line (especially when dealing with a shell script), you may find yourself in a situation where you have to perform actions like searching for a substring in a string, finding its index, as well as other things like performing comparisons and arithmetic operations. For those who aren't in the know, there exists a command line utility - dubbed expr - that lets you do all this.
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Linux expand Command Tutorial For Beginners (with Examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 0 While working on the command line in Linux, there may arise a situation where-in the requirement is to replace tabs in a file with spaces. The task isn't difficult if the file is small, but what if the file you're dealing with is huge, or worse, there are hundreds of files in which you have to make this change? Worry not, there exists a command line tool that's specifically built for this work. The tool in question is expand, and in this tutorial, we will discuss the basics of expand using some easy to understand examples.
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A Beginner's Guide to Using ed Editor in Linux (Examples Included)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 2 Did you know what kind of editors existed before screen-based editors like vi and vim came into existence? Well, those were known as line editors. They were used at a time when computers didn't have a video display, meaning interactive editing wasn't possible. One such editor is ed, which was developed way back in 1969. The ed editor still ships with many Linux distributions.
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Linux du Command Tutorial for Beginners (10 Examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 2 Sometimes, while working on the Linux command line, you might want to quickly know disk usage for a set of files or for a complete directory. There's a specific command line tool that lets you do this, dubbed du. In this tutorial, we will discuss the basics of this tool as well as the features it provides using easy to understand examples.
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Linux echo Command Tutorial for Beginners (5 Examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 1 In this tutorial, we will discuss basics of echo as well as the command line options it provides. Suppose you want to append a hard-coded line of text to a file through the command in Linux, what would you do? An obvious approach would be to open the file in an editor, and then enter the line manually. But think of a case where-in this task needs to be automated. What's your option in that case?
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Linux df Command Tutorial for Beginners (8 Examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 1 Sometimes, you might want to know how much space is consumed (and how much is free) on a particular file system on your Linux machine. There a specific command - dubbed df - that does this for you. In this tutorial, we will discuss the basics of this command, as well as some of the major features it offers.
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Linux dir command for beginners (10 examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 4 At any point in time while working on the command line, you are always inside a directory. There may be times when you'd want to list information about all files and subdirectories within a directory. This is where the dir command helps. In this tutorial, we will discuss the basics of this command as well as the features it provides.
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Software Defined Networking (SDN) - OpenFlow and OVSDB connection
Author: Himanshu Arora •
Tags: linux, networking •
Comments: 0 This article is based on OpenFlow and OVSDB connection between SDN controller and OpenFlow-based switches and provides details on connection lifecycle. We will use open source SDN controller i.e. Opendaylight (ODL) Carbon release and OpenFlow virtual switch i.e. OpenVswitch (OVS) version 2.6.0 to describe OVSDB and Openflow connection.
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Linux Date Command Tutorial for Beginners (8 Examples)
Author: Himanshu Arora •
Tags: linux, shell •
Comments: 3 While working on the Linux command line, you might find yourself in situations where-in you need to display (or even change) the current system time. Not only that, if you work in a team with members in different timezones, you may want to keep yourself updated with time-related information for zones in which other members are sitting. If you're looking for a tool that lets you do all this (and much more), you will be glad to know there exists a command - dubbed date - that does all this.
