Welcome! You've arrived at award-winning author Marcel Gagné's personal Website. I am the author of the "Moving to Linux" series of books, a regular columnist for several tech magazines, a public speaker, radio and television personality, and a well known voice in the Linux and open source universe. I created the famous (perhaps infamous) Cooking With Linux which ran for ten years in the Linux Journal. I'm also a published science fiction author and editor, a onetime Editor in Chief, a pilot, a former Top 40 disc jockey, and I fold a mean origami T-Rex.  This site is home to my insights, opinions, gripes, brags, tech stuff, and whatever else comes to mind when I have the time or the inclination to publish it. 

Mastering The Linux Shell - Advanced Permissions

In my last article, I introduced the idea of permissions in the Linux world. Some users can read or write a file, while others can only read the same. A user may also belong to a group and share the permissions of that group which might also involve the ability to execute, or run a file as a program.

Marcel the Shell

Someone suggested that I use Marcel the Shell to narrate my articles on the Linux shell. I suppose it's because my name is Marcel and I'm writing about shells. So, for your viewing pleasure, or something, here is "Marcel the Shell". 

No, he doesn't talk about Linux. 

Or command line shells. 

Nailed for Jesus

Over at Thailand's "The Nation", you will find coverage of a bizarre practice, made all the more strange by the fact that it happens each and every year. In this report, 24 penitents had themselves nailed to crosses in a recreation of Christ's crucifixion and death. They apparently leave out the death part, but they do go through the actual process of having themselves nailed to a cross, with large nails hammered into their palms by guys dressed up as Roman soldiers.

Now you've got to hand it to them (no pun intended), these are people who really truly believe. They're also not entirely sane, I'd wager. But I guess nothing says "I believe" like participating in a brutal display of torture and human sacrifice.

A lot of questions surround this practice, and I'm not even talking about the question of whether there was a Jesus who died for our collective sins. The questions are more along the lines of this:

Mastering The Linux Shell - Getting Permission

Under Linux, access to files and directories is controlled by a system of permissions. Those permissions define who can see a file, whether they can modify it in any way, and in the case of some files, whether the commands within that file (or the file itself) can be executed. By executed, we mean "can we run that program?".

Found on Wikicommons: Saint Michael parish church in Untergriesbach. Fresco at the ceiling: Last Judgment( 1780 ) by Johann Georg Unruhe - Good souls rising to heaven.Pfarrkirche St. Michael in Untergriesbach. Vierungsfresco: Jüngst

Jesus and the Resurrection. Been There. Done That.

Let me see if I get this straight . . . a long time ago, this guy was born of a virgin, performed miracles, collected disciples, then was eventually crucified, died, was buried, and rose again to redeem mankind? Does that sound about right?

I thought so, except I'm not talking about Jesus. In this case, the guy's name was Attis and he was a fairly popular Phrygian man-god some 400 years before Jesus Christ came on the scene (though the origins of the story go back as far as 1200 B.C.). Attis was born of the virgin, Nana, became the consort of the mother Goddess Cybele. Attis is sometimes depicted as a shepherd, his priests are celibate (they are in fact, castrated),  is crucified to a tree (accounts vary somewhat on this point), dies, is buried, and rises again to bring life to the world. The Attis myth reaches its peak sometime around 200 BC.

Attis isn't special though. In point of fact, guys who were born of virgins, performed miracles, died, then rose from the dead are common to many religions. Christianity adopted a lot of these old stories to make their new religion more palatable to the dominant religions of the day. As for all those miraculous things . . . well, your god wasn't much of a god if he couldn't perform miracles or had some kind of miraculous birth. Born of a virgin sounds pretty miraculous so it makes sense to start there. Water into wine? That's an old one too.

In 405 B.C., Euripedes' "The Bacchae" was released. It features Dyonisus who, among other things, is born of a virgin, turns water into wine, and has someone crucified to a tree. Dyonisus was called "King of Kings", "Redeemer", "Savior", and other familiar titles we associate with that Johnny come lately, Jesus.

Mastering The Linux Shell : Standard In, Out, and Error

Welcome to part four in my Mastering The Linux Shell series where we will wander wistfully into a land where three terribly under-appreciated but vitally important files live. You will remember that everything is a file, including directories which some people call folders. What you may not know is that your keyboard is a file, as is the screen on which you read these words.

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The Easter Story, as I explained it to my kids

My youngest son asked me about Easter today. Luckily, as a parent, I am endowed with the power of complete universal knowledge and, naturally, explaining how Easter works is child's play. Or adult knowledge, as the case may be.

Every Easter, a giant invisible white rabbit, only vaguely like the one in the famous play, Harvey, visits every house everywhere all around the world, delivering chocolates for Easter. He goes by the name, Easter Bunny.

Possessed with awesome jumping powers, the Easter Bunny doesn't need a sleigh or reindeer to cover the world. He just hops from house to house. When he arrives at a house where a boy or girl live, he slides down the chimney, in much the same way as Santa does. Unlike Santa, however, the Easter Bunny doesn't care if you've been bad or good. He has Easter eggs to deliver and by gum he's going to deliver them.

Now Santa may be rounder than the Easter Bunny but the Easter bunny is a lot taller. Also unlike Santa, the Easter Bunny can shrink himself down to the size of a fly. This is cool because if you don't have a chimney, he can come up the floor vents. Once he pops out, he returns to his normal size (about 7 feet tall). You won't see him,  of course, because he is invisible.

Once in your house, the Easter Bunny hops around, pausing to poop out chocolate Easter eggs here and there. The eggs are hidden because he's a bit shy about pooping in public so he poops the eggs behind furniture, bushes, and so on. 

Even though the Easter Bunny is invisible, you can tell when he's around because he growls like a tiger. So if you're out hunting for Easter eggs and you hear a low growl when you find an egg, that's the  Easter Bunny.

And that is what Easter is all about.

Note : Originally published 2012-04-05.

Mastering The Linux Shell : Making Things Disappear

Information begets information and eventually, there's just too much of it. I don't really believe that -- I'm an information junkie -- but there's no question that if you never delete anything, eventually, you will either use up all your disk space, or you'll have a terrible mess on your hands.

Mastering the Linux Shell : Files and Directories

Let me tell you the secret of computers, of operating systems, and of the whole industry that surrounds these things: Everything is data. Information is the be all and end all of everything we do with computers. Files are the storehouses for that information and learning how to manipulate them, use and abuse them, and otherwise play with them will still be the point of computers 20 years from now. There's a saying in the Linux world that "everything is a file" (a comment attributed to Ken Thompson, the developer of UNIX). That includes directories. Directories are just files with lists of files inside them. All these files and directories are organized into a hierarchical file system, starting from the root directory and branching out.

For the record, and to make things easier, you can safely assume that folders and directories are the same thing. The terms can be used interchangeably, but I will usually refer to them directories. If you are more comfortable thinking of them as folders, don't worry. Depending on the application, you'll see both terms used.

The root directory (referred to as slash, or /) is actually aptly named. If you consider your file system as a tree's root system spreading out below the surface, you start to get an idea of just what things look like.

Under the root directory, you'll find folders called usr, bin, etc, tmp, and so on.  And then we have the three invisible, often overlooked, but completely indispensible files on your system: standard in, standard out, and standard error. I'll tell you more about those three later. Suffice it to say that understanding and knowing how to work with all these “files” will provide you with amazing flexibility when it comes to doing your work. 

Mastering The Linux Shell

This is the first of several articles I will be writing on the subject of the Linux command shell. Feel free to consider this first entry as a polite introduction to the topic. In Windows-land, you had "CMD" or what some might remember as the DOS prompt. In Linux, we call it a command shell, or simply "a shell". There are many types of shells, each of which works similarly (e.g. they all allow you to run commands) but each sports many different capabilities. The default on Linux is called bash, or the GNU Bourne Again Shell, so named because it is based on the UNIX Bourne shell. 

If you're ready, it is time to transform you into a master or mistress of the shell. In deciding to join me here, you have identified yourself as one of the bold and curious explorers who really want to know their Linux systems. Sure, it is possible to work day in and day out with your Linux system and rarely use the command line, but the command line is power. Your reward for continuing to this next level will be a deeper understanding of your system and the power to make it do whatever you want.

The things I want to talk about here are basic commands that will serve you well throughout your time with Linux. One of the things I hope to show you is how flexible some of these commands are. With most, you can modify the basic function with command-line switches, flags, or options, and thereby have them yield far more information than a simple execution of the command itself. A little thirst for exploration will open you up to the real potential of everyday commands. 

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