installing vinyl siding fox lake soffit installation winnetka best siding lindenhurst replace siding third lake installing vinyl siding .. Chicago Drug testing

Intro to UNIX Shells

A UNIX Shell is in simplest terms, a command line interpreter, that takes the users input and gives it to the Kernel. If you are familiar with DOS, you will remember the '' that file takes the users information and passes it to the operating system in a way it can be understood by the system. With DOS you only had one type of shell, but with UNIX you have a variety, each with their own abilities, pluses and minuses.

Keep in mind as you read about these shells, that though they may have major differences when they were created, that they have been updated and many features that were once only available in a single shell, may be available in other shells. This is more of a history lesson.

The Bourne shell, named after its creator Steve Bourne is the oldest shell for most major distributions of UNIX and LINUX. Most shells today are in some fashion derived from the Bourne shell.

The C Shell. The C shell is a great shell that has many advantages over the original Bourne shell, it was the first to introduce a history (the ability to scroll up, to view past commands). Also the C Shell as the name implies also integrates a great portion of the C programming language. If you are able to program in C, you can pretty much do it all in a shell script or from the command line, if you so desired.

The Korn Shell. Named after its creator David Korn. This shell is able to do most of the things both the Bourne, and C Shell can do, and improves on them. For instance, the history feature is available, plus you are able to call up the history, edit the command, and then re-run it.

The Bourne-Again Shell. This is probably the most widely used shell to date, and is the default shell for most newer Linux distributions. Again it integrates most of the above features and improves upon them. It was developed by the Free Software Foundation.

There are many other shells out there, but chances are if you are using a UNIX style operating system, you are using one of the above mentioned shells. My personal favourite is the bash shell, which also happens to be the first one I was exposed towards, so I may be biased. However typically when shell scripting, I use the korn shell because of its programming friendly structure.

How do you know what UNIX shell I am using?

Type "ps" and then hit return at your shell prompt and you should get something similar to:

$ ps
13087 pts/1 00:00:00 bash
13121 pts/1 00:00:00 ps

The numbers under PID, TTY, TIME etc should all be different from machine to machine, and the number of lines of programs running may also. But one line you have will be probably "bash" "csh" "sh" "ksh".

Another way to check is to type the following:

grep your-user-name /etc/passwd (eg grep ken /etc/passwd)

Which will return you something along the lines of:


The last portion of that line is '/bin/bash' which tells you your default shell when you login.

Ken Dennis

In The News:

Increase Office Efficiency With One Simple Tool

When you need a phone number, you do a quick... Read More

Microsoft Great Plains: Data Conversion & Migration Scenarios ? Overview for Consultant

Microsoft Business Solutions Great Plains serves multiple industries in the... Read More

Cross-Platform Custom Software Development & Integration ? IT Strategy for Large Corporation

Microsoft Business Solutions products: Great Plains, MS CRM, Navision, Axapta,... Read More

Review of TikiWiki Content Management System

TikiWiki is open source software - it is written in... Read More

Importance of Coding Standards

Programming Help for BeginnersWe write programs to instruct computers. When... Read More

Fast Car Knoppix

Small can be beautiful! Working with Knoppix for the past... Read More

Recovering Microsoft Great Plains Customization ? Tips for IT Director

Remember nice and prosperous Clinton era? When you implemented innovative... Read More

ERP Consulting: Microsoft Great Plains Partner Future Directions

In the Clinton era the status quo was simple: you... Read More

Spyware - The Internet Devil Of Our Times!

Spyware and Adware infest over 90 percent of computers in... Read More

Online PowerPoint Presentation ? Convert PowerPoint to Flash

Although we don't know whether Microsoft ever envisioned such a... Read More

Basic Tips and tricks for Windows XP

Running Applications in Compatibility Mode With Windows XP, you can... Read More

The Religion And Philosophy Of Small Internet Business

I have always had a tendency to focus on the... Read More

Great Plains Dexterity: Customizations & Source Code Programming

Great Plains Software Dynamics, Dynamics C/S+, eEnterprise were written on... Read More

Business Planning Software

Once a business idea is selected, it is highly recommended... Read More

Tools for Customizing Great Plains

Microsoft Business Solutions ? Great Plains has captured the US... Read More

Windows Screensavers Explained

In this article you will find some background information about... Read More

Theres Gold in Your Websites Server Log

Many Webmasters have never bothered to view their website's server... Read More

Microsoft eCommerce Web-development: Great Plains eConnect .Net ? Highlights for Programmer

In our small article we'll consider Microsoft Business Solutions Great... Read More

Start Developing Your Own Software

Learning how to program software seems like a daunting task... Read More

Microsoft Business Solutions Partner ? How to Launch New IT Consulting Practice

In the new era of internet marketing the problem of... Read More

Software Process Improvement -A Successful Journey

Background: For many organizations like ours, the interim target of... Read More

Need of Document Management System (DMS)

Document Management or Enterprise Information Management is perhaps one of... Read More

RFID: Strengthen the Position for SAP; United States

SAP Inc., a global leader in client/server enterprise application software... Read More

Two Reasons to Use Timesheet Software

This short paper will expand on two key reasons to... Read More

Getting Patched with Windows Service Pack

Are you one of those people that keeps track of... Read More

lights for the street street light photos Pete's produce ..
lights for the street street light photos Pete's produce ..