Introduction to the Command Line is a visual guide that teaches the most important Unix and Linux shell commands in a simple and straight forward manner. Command line programs covered in this book are demonstrated with typical usage to aid in the learning process and help you master the command line quickly and easily. Covers popular Unix, Linux, and BSD systems.

Introduction to the Command Line (Second Edition): The Fat Free Guide to Unix and Linux Commands

Price: $15.98

In a never ending battle to ease costs, many hospitality providers today are looking at Linux POS solutions when they embark on their search for point of sale software and operating systems that will benefit the bottom line.  Issues such as cost and flexibility make Linux an attractive choice. However, just as many operators may be asking, “what exactly is Linux anyway?”

Linux is a free Unix-type operating system created by Linus Torvalds. Developed under the GNU General Public License , the source code is freely available to everyone.  According to IBM, Linux is currently the fastest growing server operating system.

Once businesses have decided on an operating system,  the next task is usually sourcing out a POS (point of sale) system.  At the best of times, sourcing out a POS system for your business operation can be a confusing, time consuming and arduous job.  Throw in the added obstacle of having to select point of sale software that can actually run on your operating system, and it’s easy to see why owners and managers often shy away from this difficult task.

Interest in Linux point of sale solutions has grown dramatically in the last few years.  The reason why is simple; Linux, as an operating system, is more cost effective, flexible, and allows for greater freedom of choice in software than more mainstream operating systems.  Linux is also very cost effective in regards to licensing, installation, administrative and support costs. Linux can offer all these features without sacrificing functionality.  For retailers and hospitality/restaurant operators alike, cost and ease of use are king, and reasons such as these can make the difference between a business that succeeds and a business that fails.

POS software providers have been slow, however, to jump on the Linux bandwagon.  Currently, there are few well-known or enterprise-wide POS software packages available for Linux. One company, however, has seen a niche in the market and has embraced it head on. Volanté POS Systems, of Toronto, Canada, offers a POS solution that has been developed entirely in Java.  Java is cross platform compatible and operates in multiple environments – this gives the user freedom to choose Linux, Windows 2000/XP, or Windows and Linux. For many operators, having a choice is key.

Not only does Java provide cross platform compatibility, but like Linux, using Java POS solutions can be cost effective as well, as Java allows users the opportunity to save on additional Windows license fees, as an example. Java’s open standard architecture allows the entire system to be compatible with third party industrial applications. Users are free to choose their operating environment and are not bound to costly proprietary restrictions.

Volanté also offers integration with Windows-based back office applications. This flexibility is rare in the POS industry.  For more information on Volanté’s Linux & Java POS solutions, visit their website at  www.volantesystems.com.

From a retail perspective, Linux is definitely catching on.  Burlington Coat Factory, for instance, has already rolled out Linux in all of their locations, both as a desktop and POS system.  Other retailers/restaurateurs’ currently using Linux in their stores include: Papa John’s, Garden Fresh, Mark’s Work Wearhouse, Home Depot, and Gap, to name a few.

The push for Linux isn’t just in North America, either.  Asian governments are looking closely at Linux, hoping it will lead to the development of a domestic software industry that isn’t hostage to foreign licenses.  According to Linux Insider International, “Asia is emerging as a key battleground for the open-source movement. The Japan-China-Korea (JCK) partnership, is the latest in a string of initiatives to promote Linux.”

So, when choosing an operating system and subsequent point of sale system, consider Linux. Discover for yourself why Linux is the fastest growing server operating system.

Unix and Linux are both POSIX compliant operating systems. POSIX defined a standard interface to the low-level operating system which greatly reduces the amount of work required to produce UNIX and Linux software.Unix and Linux software development

The standard user command line and scripting interface was based on the Korn shell. Other user-level programs, services and utilities include awk, echo, ed, and hundreds of others. Required program-level services include basic I/O (file, terminal, and network) services. POSIX also defines a standard threading library API which is supported by most modern operating systems.

Currently POSIX documentation is divided in three parts:

POSIX Kernel APIs

POSIX Commands and Utilities

POSIX Conformance Testing

Linux Development requires both POSIX and 3rd party/native GDI and GUI frameworks to create usable Linux and UNIX software. DOTNUTSHELL can create highly scalable and usable POSIX software which can be run on UNIX and Linux. The software can range from simple utilities to distributed software which has to be run on heterogenous platforms such as Linux, UNIX and Windows.

Linux and UNIX development is also the desired platform and framework for the creation of embedded software:Embedded software and embedded systems, are those that require 100% of resources shared across a single platform often used to monitor, update and control hardware.

DOTNUTSHELL has experience in creating robust, efficient embedded software running as a monolithic Operating system, or a Kernel add-on in an Embedded Linux distribution.

It is the responsibility of the underlying embedded software system to maintain state information, persist changes to hardware configuration as well as gaurantee transaction and concurrency control at the hardware interface-level.

We have experience in creating:

MontaVista based embedded software

Embeddix based embedded software

Linux Driver creation

low-level hardware and bus interface strategies and mechanisms

I/O mapping and application/kernel space mixing

Real-time application development

Cross platform development

Assembler/C/C++ based embedded software development

POSIX development

RISC/PowerPC405 & 82xx, MIPS Development

The Linux Foundation announced April 8 its annual sponsorship of independent IDC predictions about how the Linux ecosystem will grow over time. The answer is “a lot” but exactly what you’d expect in relationship to the UNIX ecosystem.

Law enforcement recently has been following the general tide of government and public service groundswell by seeking computing solutions in the Linux direction. Particularly in law enforcement, their needs match well with open source software. They have to work lean on a taxpayer’s budget, and open source is free or low cost. They need top security, and Linux is still the highest-scoring operating software in official government assessments. They need mission-critical reliability, and Linux is so stable, it doesn’t just outrank the competition in stability – it makes the competition disappear!
Some recent examples of law enforcement agencies finding a solution in open source:
* Kent Police have lowered the cost of running their major criminal investigations system by a factor of 90% using Novell Linux Open Enterprise Server. The migration to Novell enabled Kent to scale up their Holmes II investigation system to work on larger projects with a broader scope – something they’d never been able to do before. They were also able to run it on their cheapest hardware they could find, thanks to Linux’s light requirements. A new policing operating system, named Genesis, is now being tested for scalability on Linux servers.
* Delivery of the first Linux systems to the West Yorkshire police force could see police forces throughout England and Wales unanimously switching to Linux desktops in a new pilot scheme. The deployment is taking place under a contract awarded by the UK Police IT Organization. If successful, it will lead to over 60,000 desktops deployed. In West Yorkshire alone, the installed base is around 3,500, and a spokesman reckoned that the savings from this would be around one million pounds per year!
* The New South Wales Police department is currently undertaking a major upgrade to its information infrastructure, made necessary due to the increasing volume of data handled by the force, and they’re switching to Linux systems to handle the load. Because the Linux systems are proving so reliable, they are looking forward to the higher capacity network more efficiently archiving and transmitting data stored as evidence, such as surveillance videos and audio material.
* Scottish police forces have also developed a Linux-based system for ensuring that they comply with the Freedom of Information Act legislation, an act which is intended to facilitate ‘open government’ by allowing the public to request access to government data. Since open source and open information go hand in hand, the system has scaled easily and saved tons of labor. The force doesn’t have to worry about proprietary media formats interfering with the public’s ability to access the data, and the efficiency of the Linux system allows a lot of manual tasks to be automated where they couldn’t before. The system is literally returning officers to the streets because it has saved everyone so much work.
* Police in the city of Munich have switched 14,000 of their department computers from Microsoft’s Windows operating system to Linux. The motivation for the decision was to make the government less dependent on one information technology supplier, and to save money while increasing capabilities. One technology analyst even compared the break-through migration to the fall of the Berlin wall, referring to the oppressive requirements of dealing with a proprietary software company’s agenda.
That government feels friendly with open source should come as no surprise. Traditionally, the Internet has been 80% Linux and Unix-based systems since its creation. The first Internet services were started and maintained by government providers, who used Unix system’s built-in multitasking features and excellent speed to create a fast, reliable network. Linux, a modern version of that Unix ideal, has already established itself as the leading system for server-room deployment, but now the effects are beginning to trickle down to the desktop user level and workstation deployments, where they are discovering that Linux systems have workspace-ready features built in which other commercial operating systems are just now beginning to discover and implement.
Furthermore, Linux systems come with the guarantee that because they are open source, no commercial company can restrict their usage in the future. A platform ported to Linux can stay on Linux, without support dying out and constant upgrades creating problems down the road.
Finally, the inherent security of the Unix computing model guarantees the effectiveness of Linux without the worries over security problems. Because there are in effect no viruses which can infect a Linux system known, and no critical security exploits found in the systems even by government security standards, departments are also considering Linux as a measure to protect our national data under concerns over national security and the terrorist threat in our modern times.

What is a BSD Unix?

BSD family of Unix systems is based upon the source code of real Unix developed in Bell Labs, which was later purchased by the University of California – “Berkeley Software Distribution”. The contemporary BSD systems stand on the source code that was released in the beginning of 1990′s (Net/2 Lite and 386/BSD release).

BSD is behind the philosophy of TCP/IP networking and the Internet thereof; it is a developed Unix system with advanced features. Except for proprietary BSD/OS, the development of which was discontinued, there are currently four BSD systems available: FreeBSD, NetBSD, OpenBSD and Mac OS X, which is derived from FreeBSD. There are also various forks of these, like PC-BSD – a FreeBSD clone, or MirOS, an OpenBSD clone. The intention of such forks is to include various characteristics missing in the above BSD systems, on which these (forks), no matter how well they are designed, only strongly depend. PC-BSD, for example, has more graphical features than FreeBSD, but there are no substantial differences between these two. PC-BSD cannot breathe without FreeBSD; FreeBSD or OpenBSD are independent of one another.What is Linux?

Albeit users like to use the term “Linux” for any Linux distro including its packages (Red Hat Linux, Mandrake Linux, etc.), for IT professionals Linux is only the kernel. Linux started in 1991, when its author, Linus Torvals, began his work on a free replacement of Minix. Developers of quite a few Linux system utilities used the source code from BSD, as both these systems started parallelly in about the same time (1992-1993) as Open Source.

Today, there are a few, if not many developers of their own kernels/operating systems (FreeDOS, Agnix, ReactOS, Inferno, etc.), but these guys simply missed the right train in the right hour. They did not lose anything except for the fact that they may be even better programmers, but without the public opinion acknowledging this at large. Linus built his fame also from work of many developers and he went on board in the right time. Linus deserves a credit as a software idea policy maker and he helped very much in this respect.(Open)BSD vs Linux

It is often difficult to say what is better if you compare two things without regarding the purpose of their use. Mobile Internet may appear better for someone who travels often, but for people working at home such mobility is not necessary. In this view, it is a stupid question when someone asks: “What is better, a mobile or static Internet?” It all depends…

If you compare Linux and OpenBSD in their desktop environment features, Linux offers more applications than OpenBSD; but in a server solution BSD systems are known to be robust, more stable and secure, and without so many patches distributors release soon after their new version of Linux slithered to light.

BSD systems are based upon real Unix source code contrary to Linux, which was developed from scratch (kernel).Differences between BSD and Linux

1) BSD license allows users/companies to modify a program’s source code and not to release changes to the public. In other words, BSD licenses allow commercial use and incorporation of a code into proprietary commercial products. This is how Microsoft incorporated BSD networking into their products and how Mac OS X earns money through muscles of FreeBSD.

Linux uses GPL license for most of the time (applications in Linux can also have a BSD license – or any license; it is up to developers how they decide). With a GPL-licensed program anybody can change the source code, but he or she MUST share it with the Open Source community to make sure that everybody will benefit from such a change.

2) BSD has the so-called “core system” (without packages). The core system consists of basic utilities (like ssh, fdisk, various commands like chmod or sysctl, manual pages, etc.) and anything beyond this is strictly seen as an add-on. Linux (not only the kernel, of course) is usually packaged as the whole system where this difference is not seen.

3) On BSD systems, all add-on packages are strictly installed into the /usr/local directory: documents to user/local/share/docs/application_name; themes and other things to /usr/local/share/application_name; binaries to /usr/local/bin/application_name. By application_name we mean a program’s name, so if you install IceWM, for example, its binary will be here: /usr/local/bin/icewm. With Linux, on the other hand, all applications get mostly installed into the /usr/bin directory.

4) BSD systems use the system of “ports”, which are fingerprints of applications in the /usr/ports directory, where a user may “cd” and execute a make command, which will download, via a directive contained in such a fingerprint’s code, the application’s source and the system will compile it as well. “Ports” are actually add-on packages for BSD systems and they are also packaged in packages repository of a concrete BSD system. They can be installed as binaries, too, with use of the “pkg_add” either directly from the Internet or locally. But “ports” have that advantage that if an author of any package makes a new version, a user can immediately get its newest/updated version. Packages released for a particular BSD version (like OpenBSD 4.1) are not updated and users have to wait for a new BSD release (like OpenBSD 4.2).

5) BSD systems have also their stable version. With FreeBSD, for example, you have a FreeBSD-Release (a version that can be used normally), FreeBSD-Stable (system more profoundly audited for bugs and security holes), and a development version – Current, which is not stable and not recommended for a regular use. Some Linux distributions started to imitate this philosophy, but with BSD systems this way of making distributions has become a rule.

6) Of course, the kernel is absolutely different.

7) BSD has FFS file system; it is the only file system on BSD’s contrary to Linux, where you can use dozens of file systems like ext2, ext3, ReiserFS, XFS, etc.
BSD systems divide their partitions internally. This means that after installing a BSD system to a hard disk, programs like fdisk, Partition Magic, Norton Ghost and many others will not see this internal division of a BSD (FFS) disk; thus, repartitioning of a disk is not such a pain when administrators require a rigorous partitioning (for /home, /tmp, /var, /etc directories). As a consequence, the naming convention also differs a little: a disk – /dev/ad0s3b in FreeBSD indicates that you deal with “slice” 3 (“s3″), which is the equivalent of Linux /dev/hda3; the internal “partition” has the name of a letter: “a”, “b”, “e”, etc. (“b” is a swap partition). BSD systems also use different naming conventions for devices (disks, etc.).

9) Unless you make a good kernel hack, BSD systems can only be installed into the primary partition. This is not the rule with Linux. However, as BSD systems offer the above-mentioned internal division of partitions, this is not any pain. PC architecture for disks (IDE) follows the rule that you can have only four primary partitions. We will illustrate this on Linux: /dev/hda1 (note: first partition on master disk on first IDE channel), /dev/hda2 (second partition), /dev/hda3 (third partition), /dev/hda4 (fourth partition). PC architecture allows creation of the so-called logical disk on a physical disk (/dev/hda5, /dev/hda6, etc.). You can have as many logical disks/partitions as you wish and you can also install Linux into these “logical disks”. On the other hand, installing a BSD OS into such a “logical partition” is not normally possible.

10) System configuration is manual for most of the time, but various clones like PC-BSD break this convention. The manual approach is a very good thing, as administrators have everything under control without being pushed to waste time in a labyrinth of bloated configuration menus. A good comparison is to imagine a car mechanic repairing the car’s engine covered by a thick blanket. To give you even a little better example – you will hardly find a Linux distro that does not have a default X startup (graphical environment). Of course, you can switch off the X environment during the installation configuration, but if you keep forgetting like me and forget to switch this off, or you have difficulties to find it in the menu somewhere, you realize that most Linux distributors do indeed impose on us only one approach – to put our fingers first on the thick blanket, then on the engine. If you are a good administrator, you do not usually trust vendors who program you how to use Linux – you are the boss and you must have your own freedom. However, in most cases you lose few hours instead by deactivating various services, which are, unfortunately, not even necessary but almost always activated by default. Linux is praised both for being a good desktop and server, but administrators of a good server do not need X. The more software is stored on your hard disk, the more security problems you will face, because it is impossible to audit every package in every unthinkable situation. Good and secure systems are always tight, light and simple.

11) All BSD systems have a Linux emulation support. Running BSD binaries on Linux is a little harder.

12) BSD systems have less support from driver vendors, thus they lag behind in this view (they are not worse, but many vendors support only Microsoft and Linux). With a BSD system you must carefully research the Internet for supported products/chipsets before purchasing any hardware.

13) BSD systems do not use the Unix System V “runlevel scripts” (initialization startup scripts) like Linux.

14) BSD kernels can be set to several security levels. This is also possible with Linux, but BSD’s have taken a very good care of this kernel-tuning feature, which makes it even impossible to change something in files in higher security levels – you cannot delete them.

15) BSD’s have everything under one ROOF. Various Linux programs are often not even compatible with other Linuces. For example, if you install a SuSE RPM package on Mandrake, it may not work. BSD’s have one solid crown of power. If you move from Linux to FreeBSD, you will soon find out that you got out of this chaos. Do you want a package? Just visit: http://www.freebsd.org/ports/ and download it. Unless its developer made some programming errors, it will always work.

16) Generally, BSD systems boot and reboot faster than Linux. Linux can do this, too, but it must be tuned. It is very surprising that Linux is shipped, on the one hand, on huge DVD’s and, on the other hand, it has a compressed kernel. BSD systems do not use (but they can) a default kernel that is compressed, thus the system boots always faster. As I mentioned earlier in this article, Linux vendors program users to use various, often unnecessary services. I do not need SAMBA (file and print services) and many other things as well. Linux reboot process takes longer because various services running on Linux need time for deactivation. Many Linux users do not even know what is the purpose of these services.

17) In comparison to BSD, most Linux distributions are overbloated. Few good users noticed this some time ago and a new trend in the Linux world started with ideas to get closer to a BSD-style use. One of such distributions is Gentoo Linux, but also Slackware Linux, which has preserved a very good shape since its first release (1993). The Gentoo “About” page (http://www.gentoo.org) says that, “Gentoo is a free operating system based on either Linux or FreeBSD…” Therefore, if you use Slackware or Gentoo, these Linuces will always reboot faster than any other Linux.

18) If you compile programs from ports, you will not stumble into compilation errors. BSD packagers prepare their packages carefully, so that users will always compile them successfully. This does not always happen with Linux.Conclusion

I am the author of One Floppy CD Audio and MP3 Player, and a single floppy OpenBSD router. I really like all BSD systems. If you are interested, look into FreeBSD documentation, which is one of the best. It will give you a very good overview of history and hard work done in the development of these robust systems. Today, BSD Unices are the only quality alternative to Linux in the Open Source world.

Copyright (c) Juraj SiposAuthor’s website about FreeBSD and OpenBSD

What is Linux?

Linux is an operating system, like Microsoft Windows, MacOS, or Unix. It was created as a hobby by Linus Torvalds, a student at the University of Helsinki in Finland. What most people don