Linux Commands » Number

The Top Ten Concepts for Beginners to Linux – Number 3, Users

admin — Sun, 05 Sep 2010 15:41:32 +0000

Unlike Windows, Linux users must have an account. Account? permissions granted such as reading and writing files and execution? n programs. The accounts are combined into groups to simplify MANAGEMENT? N. Users who are members of a particular group can be assigned additional permits to facilitate the process of access to common files. Let’s see m? S? c care? mo Linux handles these users. A pr? Maximum art? Ass view the permissions and groups.
Linux offers two categories? As users, ordinary users essentially limited to working with the Creation? No files, and the superuser or root, and the management? N the system? authorized to do almost anything. The status? No real? obviously, a little ‘m? s? complex. For example, users can? granted limited access to additional files of interest? s for all. The superuser can? assign certain privileges to other members to reduce overwhelming workload.
The root user? the? only person authorized to execute the adduser or useradd pi? complicated. If you downloaded Damn Small Linux? You can try these commands in Windows. In response to the Linux adduser command requires a user name, password? Ay, a continuation? N some optional fields that can be skipped. An organization? N with many users or duty? An have a pol? Tica for Resolution? No user names.
Key? a key element in the protection? of the safety report? tica. It is pod? To write an article? Ass on the password? Ay selection? N the password? A. Remember that Linux is between letters lower case and May? Letters. If you’re new to the team? Right? Try to work with password? As f? Ciles to remember at first. But to protect your account and the information? N depends on your password? As dif? Ciles guess.
When Linux creates his story as well? N creates a directory whose name? f? easy to remember. If your account name? Lucy then your working directory? / Home / Lucy. I’m going to discover the path to working directory for Windows systems Lucy.
Damn Small Linux share a character? Stica interesting with many other Linux systems. The system administrator can? provide new users with copies of some folders and place them in the / etc / skel before launching the command adduser.
? C? Mo? system administrator is supposed to handle the Creation? n tens, hundreds of thousands, or even new users, for example, the beginning of the semester? ? He or she will not have? time to carry out this demanding task. And there? so that the lost password for root must be disclosed to the worker who is assigned this task. The answer? simple: write a program to create these new accounts. This program can be? The account will also interface? n SPIFF Creation, use, and maybe grab a bit of information? No sources such as log files of students.
Of course we do not want to create users without the possibility? elimination. The process of living? rather complicated and plans to eliminate lost password file / etc / passwd, the elimination? n all user files, and other activities? such as backup of the information? n essential. The following art? Ass analyzes the concepts of permissions and groups.

The Top Ten Concepts for Beginning Linux Users – Number 4, Permissions and Groups

admin — Sat, 28 Aug 2010 14:11:34 +0000

Top Ten Concepts for Linux Beginners – Number 2, Directories

admin — Fri, 23 Jul 2010 04:42:43 +0000

The Linux people like to claim that the directories are actually just another file type. This statement may be misleading. We have seen in a previous article that creates a file with a file editor. We will see later in this article how to create a directory.
So what is a directory of Linux? A directory is a collection that may include one or more directories, one or more files, or in fact be empty. You can think of a file directory as a folder or notebook computer containing separator sheets (directories themselves) and pages (files.o) Like a sheet of notebook can not contain a separator, a Linux Files can not contain a directory.
Up to now take our comments on the Linux for the Windows directory. Now let’s look at some differences between these two systems. First are the naming conventions. Linux is still distinguishes between lowercase and capital letters in directory names. Microsoft Windows is not. For example, Linux is pay12june Pay12june and are like two different directories, as different as the directory and heighho pay12june. These directory names are used as file name in the preceding article. While Linux has a private directory and file names, in general we can not say the name if it is a filename or a directory name. So beware. Linux helps us here ‘command ls, which lists the contents of a given directory usually lists the files and directories in different colors.
Directories are hierarchical. They look like a tree or a tree. But unlike a tree (or Microsoft Windows), Linux has a single root. The root, designated as / is at the top instead of at the bottom of the hierarchy. Just below the root directory is several subdirectories. For example, the directory / home is a child of / root. The number and names of the subdirectories of the first level varies from one version of Linux to another. For example, some Linux distributions include a directory / root, while others do not. The root directory / (and subdirectories, are used both terms) is a child, the root directory.
The / home directory is important. E ‘divided into subdirectories, one for each user. We like to work with Damn Small Linux, a free version of Linux that runs on the Windows desktop and requires only 50 megabytes of disk space. Damn Small Linux automatically creates a user called dsl whose home directory is / home / dsl, a work area reserved mainly for this user. All versions of Linux divide the directory / home user directory according to this simple naming convention.
Linux provides several commands to process the directory. For example, the command mkdir creates a directory. The command rmdir removes a directory, but in the simplest case when empty. The cd command changes the working directory, the directory where you are. The pwd (print working directory) command displays (print) is not the working directory. Beginners should run this command frequently to reduce errors. For example, if the user of DSL, I think we are placed in / home / DSL, but are located in the / you can not save files with a single command. Why? Because they lack the necessary authorization, the subject of our next article.

The Top Ten Concepts for Linux Beginners – Number 7, Runs on Obsolete Computers

admin — Tue, 26 Jan 2010 08:41:51 +0000

The Top Ten Reasons for Learning Linux, Number 8, More Control Over the Computer

admin — Sun, 20 Dec 2009 23:42:31 +0000

The Top Ten Concepts for Linux Beginners – Number 7, Shells and Utilities

admin — Wed, 16 Dec 2009 22:37:27 +0000

A shell is the command interpreter program that serves as an interface between some users and the operating system itself. We say some users because most users rely on the graphical user interface. The Windows shell is the DOS command line interface accessed by clicking on Run and then entering the cmd command. The Windows graphical user interface is Explorer. This article describes the Damn Small Linux shell interface and several utilities, useful programs that may be launched from the shell. A subsequent article will describe the corresponding graphical user interface.
Why would anyone want to bother with a shell when the prettier, easier-to-learn and easier-to-use graphical interface is available? The answer is: It depends who you are and what you want to do. For system administrators or their associates it’s often much less cumbersome to use the shell rather than the graphical user interface. While Damn Small Linux commands may be quite arcane, they can be very powerful. And efficient. The Linux tools for performing administrative and other technical tasks admittedly take time to learn and master. But it does the job and does it well. In all fairness, many Windows systems administrators often apply command-line utilities. But they don’t have a powerful shell to help them do their work.
Historically Unix used the Bourne shell, the C shell based on the C programming language, and the Korn shell. Linux’s most widely used shell is Bash, also spelled BASH, the (Bourne-Again Shell). Damn Small Linux offers many shells but most people go with Bash both to communicate interactively with the operating system and to write programs known as shell scripts. If you program in Linux no matter which programming language you use you should learn some Bash specifics.
Utilities enable you to handle some very sophisticated processing. You can think of them as commands or as prewritten programs. Unix-Linux people often send the output of one command or utility to another command or utility for further processing. For example, the ps command displays active processes. It tends to generate voluminous output, especially in a busy system. Let’s say that you are interested only in the processes associated with a given terminal. You send (the technical term is pipe, expressed by the | character) the output of the ps command to the grep utility which looks for patterns within the input. You code a single line, multipart command to obtain the list of processes associated with that particular terminal. Unix and Linux are well known for elegant solutions. In contrast the Windows solution to this information need is much more clumsy.
The grep utility has many other uses including validating e-mail addresses. Let’s say that your web site asks potential subscribers to furnish their e-mail accounts when signing up for a newsletter. A sophisticated but relatively short statement coded in grep could validate e-mail accounts.
Other Damn Small Linux text processing utilities include the related egrep and fgrep commands, mawk a pattern scanning and text processing language, sed an editor that handles large files, and diff a utility that compares files. DSL provides utilities that compress and archive files, and a wide range of other utilities. If you need them, these Linux utilities can be quite useful and time-saving.
Our next subject is Linux programming support.

Top Ten Concepts for Linux Beginners – Number 1, Files

admin — Sat, 12 Dec 2009 21:39:19 +0000

Of course if you are used to Microsoft Windows you are familiar with the concept of files. This familiarity means you won’t have to start from zero to learn about Linux files. However, you will have to relearn several concepts and techniques to work with files in the Linux environment, whether using Damn Small Linux or other versions. You can do several great things with Linux files that you can’t do easily or at all under Windows. This could be just one more reason to switch from Windows to Linux.

Files have unique names. This rule is not as simple as it may seem. There is no conflict between a hard disk file named pay12june and a file named pay12june on your removable USB flash drive. In fact, be sure to backup all your important files. Don’t worry if your hard drive file is erased or becomes corrupted and illegible, simply access the one on your flash drive. You could also have two files named pay12june on your hard drive in different directories. Directories, collections of directories and files, will be discussed in the next article in this series.

Linux distinguishes between lower-case and upper-case characters in file names. Microsoft Windows does not. For example, Linux treats pay12june and Pay12june as two different files, as different as pay12june and heighho. Windows users will have to adapt to this major difference. Even though I am a Linux fan I don’t see any advantage in the Linux way of naming files. Maybe I have spent too much time in the Windows environment.

File names should be relatively short. The allowed maximum is 255 characters but working with long file names is no fun and in fact is asking for trouble. Linux file names may not contain the character / which has a special meaning. To avoid misunderstanding don’t include special characters such as $ and & in your file names. Doing so could cause confusion and lead to hard-to-find errors. For the same reason don’t call your files by special Linux names such as etc.

Linux sometimes applies file extensions; common examples include . c to indicate a C-language program and . htm or . html to indicate one type of web page. Savvy Linux users often avoid coding the file extension but rely on the file directory to indicate the file type. Don’t give a Linux file a misleading file extension.

Use an editor to create or modify a text file. The old fashioned vi editor has been replaced by more powerful, user-friendly editors. Most versions of Linux come with several editors. Damn Small Linux, a popular version that runs under Windows, includes several editors such as Beaver that come quite close to being intuitive.

Linux provides an enormous variety of commands for processing files. Many of these commands are mnemonic; for example the command cp is used to copy files. Many commands include a wide variety of options. Consider the ls command, somewhat similar to the DIR command in the Windows environment. This seemingly simple command is quite rich and offers dozens and dozens of options many of which have no equivalent in the Windows environment.

Linux commands can be thought of as verbs. Just like most English sentences include more than a verb (go, jump) complete Linux commands contain the command itself and one or more objects. To copy a file you not only need to specify cp but also What and Where. For example, the command cp pay12june backuparea means copy the pay12june file into the backuparea directory.

Linux syntax (grammar rules) is quite strict and does take time to learn. But mastering Linux and associated technologies can lead to employment. The next step is mastering Linux directories.