Setting File Permissions On A Unix Server

File permissions are one of the strengths that the Unix world has had over it's Windows contemporaries. Permissions are a means to control access to information on a computer, on a file by file basis. There are several layers of control, and these will be discussed below.

For the purpose of this series of tutorials, I have been using a free FTP program called Core FTP Lite to upload files to my server. I am using this program to describe my examples.

Ok, to begin, let's say that we have uploaded some files to a server.

We are discussing uploading scripts in general here, and certainly for many scripts, the creators may well specify certain 'permissions' that need to be set in order for the scripts to operate correctly. Let's take a look at a set of files on a server. In Core FTP Lite, the server files are shown in the right hand pane. Select one and then right click on the highlighted file.If you use a different FTP client, I expect that the layout will be very similar.

Run the mouse down to the bottom of the menu and select the item marked 'Properties'. Click on this option, and another dialog will appear.

You will see that the file in question (in this case a directory) is being shown in the 'File' field at the top of the screen.

What we are really interested in, is the tick boxes in the bottom half of the screen. These hold the file 'privileges' or 'permissions' for this file or directory.

There are three types of 'permissions' available.

* User - which means the person signed on who is setting the permissions

* Group - which means a specific group of users for whom access to the file has been granted

* World - which means everyone.

Within these groups of users, there are 3 distinct types of permissions

* Read - which means that permission to read a file, but not alter it or run it

* Write - which means permission to write to a file and change it

* Execute - which means permission to execute a file, which is important in the case of scripts for example.

Permissions are sometimes called by these names (read, write, execute) but are more commonly referred to using letters 'rwx'. In addition, permissions are sometimes referred to by a single number '755' for example. In the picture above, you will see a value box. This is the number being referred to. How is this number made up? Well let me explain.

Read
User 400

Group 40

World 4

Write
User 200

Group 20

World 2

Execute
User 100

Group 10

World 1

Each value for each setting is shown. Try them out by ticking them, and see the number in the 'Value' field change accordingly.

So, lets look at a real example

Can you see how the number 755 is made up? Add up the individual values from the value table and see.

So hopefully you can see, that setting file permissions with the right tool is not hard at all.

Charlie Cory worked or many years running a HelpDesk for a software house, and has experience in many operatng systems and technologies. The online aticle contains many pictures which help bring this tutorial to life.

Setting file permissons

---

USB Drives - What to Look For in a USB Device

Those small USB drives have so many names, pocket drives,... Read More

The Advantages of Portable MP3 Players

With their solid-state technology, compact size, and abundant memory, portable... Read More

Dont Let the Internet Overstimulate Your Mind

The Internet is an awesome tool, but be careful and... Read More

Improve PC Performance - 6 Tips You Must Know

Are you frustrated with your PC?Is it feeling sluggish or... Read More

Faster Browsing Tips

IF WE say that it was mainly because of the... Read More

Ergonomics and Healthy Computing - Positioning Your Body For Maximum Comfort At Your Computer

Do you remember the old saw about how computers would... Read More

Tips For Getting Technical Support Help Online

Sometimes your PC will start acting strange for no apparent... Read More

Troubleshooting Computer Freeze (Lockup) Problems

How familiar does the following sound? Your computer was working... Read More

Cisco Certification: Building Your Home Lab, Part II

In the first part of this home lab tutorial, CCNA... Read More

Cisco Certification: What To Expect On Exam Day

Cisco Certification: Taking Your First Certification ExamYou've studied hard; you've... Read More

Printing Multiple Copies of Photos

I do a holiday letter every year and send them... Read More

Customize Your Portable Player with an MP3 Player Accessory

Everywhere you look today people are listening to personal audio... Read More

EDTV vs HDTV

Confused by EDTV vs HDTV? We don't blame you. The... Read More

Portable DVD Players - Things To Know

In my humble opinion nothing makes a long trip easier... Read More

Why Get a Microsoft MCSE Certification?

In the years of the dot com boom and bust,... Read More

A Tale of Two Regeds

Tech support tells me to type 'regedt32' as opposed to... Read More

JVCs First Three-Layer Combo-Disc Blu-Ray / DVD

JVC developed and used a high-performance reflective film to produce... Read More

Password Nightmares

Good Morning Mr. Sampson. Please type in you Personal Identification... Read More

Why Using an Ad Blocker Can be a Bad Idea

Ad Blocking is getting to be a common sport on... Read More

Spyware Remover

Your first step in removing dangerous infections from your computer... Read More

Flash Your nVidia Video Cards BIOS

You will need the following:1. 1.44MB FDD (floppy)2. NVFLASH utility... Read More

How To Recognize The Telltale Signs Of Spyware

Spyware is the software that collects information about your online... Read More

Why Build Your Own Gaming Computer?

The best way to get the gaming computer that you... Read More

Bluetooth Headphones For Your PDA

Nothing is worse than having to negotiate all kinds of... Read More

10 Easy Steps to Speed Up Your Computer - Without Upgrading

1. Empty the Temp directory regularly. To do this, make... Read More

An All Too Familar Pain

Lost & Found for the 21st CenturyIn today's hectic world... Read More

Healthy Webmasters Choose Ergonomic Computer Products

Webmasters usually sit at their computers much longer in a... Read More

Getting Started with HTML

The basic language of the internet is html. If you... Read More

Are You Well Protected?

Winter?the official start of the cold and flu season. Though,... Read More

Anti-Skip Protection on Mp3 Players

There have been some questions on anti-skip protection on mp3... Read More

Does Microsoft Show Hackers How To Attack?

After another security hole recently surfaced in Microsoft's Windows operating... Read More

Quick System Restore with ASR Backups

ASR (Automated System Recovery) is a feature available on the... Read More

Have You Invited A Spy Into Your Computer?

Yes, it's true. You may have inadvertently invited a spy... Read More