mkdir Command

NAME

       mkdir - make directories

SYNOPSIS

       mkdir [OPTION]... DIRECTORY...

DESCRIPTION

       Create the DIRECTORY(ies), if they do not already exist. Mandatory  arguments  to  long  options are mandatory for short options too.

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rm Command

NAME

       rm - remove files or directories

SYNOPSIS

       rm [OPTION]... FILE...

DESCRIPTION

       This manual  page  documents  the  GNU version of rm.  rm removes each specified file.  By default, it does not remove directories.

If the -I or --interactive=once option is given,  and  there  are  more than  three  files  or  the  -r,  -R, or - -recursive are given, then rm prompts the user for whether to proceed with the entire operation.   If        the response is not affirmative, the entire command is aborted. Otherwise,  if  a file is unwritable, standard input is a terminal, and the -f or --force  option  is  not  given,  or  the  -i  or  --interactive=always  option is given, rm prompts the user for whether to remove the file.  If the response is not affirmative, the file is skipped.

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mv Command

NAME

       mv - move (rename) files

SYNOPSIS

       mv [OPTION]... [-T] SOURCE DEST

       mv [OPTION]... SOURCE... DIRECTORY

       mv [OPTION]... -t DIRECTORY SOURCE...

DESCRIPTION

       Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY. Mandatory arguments to long options are mandatory for short options too.

       --backup [=CONTROL]                 make a backup of each existing destination file

       -b                                                  like --backup but does not accept an argument

       -f, --force                                                  do not prompt before overwriting

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CP Command

NAME

       cp - copy files and directories

SYNOPSIS

       cp [OPTION]... [-T] SOURCE DEST

       cp [OPTION]... SOURCE... DIRECTORY

       cp [OPTION]... -t DIRECTORY SOURCE...

DESCRIPTION

       Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY. Mandatory  arguments  to  long  options are mandatory for short options too.

      -a, --archive                                  same as -dR --preserve=all

       --backup[=CONTROL]      make a backup of each existing destination file

       -b     like --backup            but does not accept an argument

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Which Command

NAME

       which - shows the full path of (shell) commands.

SYNOPSIS

       which [options] [--] programname [...]

DESCRIPTION

       Which takes one or more arguments. For each of its arguments it prints to stdout the full path of the executables that would have been executed when this argument had been entered at the shell prompt. It does this by searching for an executable or script in the directories listed in the environment variable PATH using the same algorithm as bash(1).

      This man page is generated from the file which.texinfo.

OPTIONS

       --all, -a           Print all matching executables in PATH, not just the first.

       --read-alias, -I Read aliases from stdin, reporting matching ones on stdout. This is useful in combination with using an alias for which it self. For example

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who command

NAME

       who - show who is logged on

SYNOPSIS

       who [OPTION]... [ FILE | ARG1 ARG2 ]

DESCRIPTION

       Print information about users who are currently logged in.

       -a, --all                             same as -b -d --login -p -r -t -T -u

       -b, --boot                                      time of last system boot

       -d, --dead                                     print dead processes

       -H, --heading                    print line of column headings

       -l, --login                                      print system login processes

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Pwd Command

NAME                            
                  pwd - print name of current/working directory

SYNOPSIS                     pwd [OPTION]...

DESCRIPTION

       Print the full filename of the current working directory.

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Redhat Enterprise linux 6 Installation

RHEL-6 Installation Part 1

RHEL-6 Installation Part 2

RHEL-6 Installation Part3

IF you have any question, quarry, suggestion please comments or email to Admin. Thanks

The Power of ls Command

NAME

       ls - List directory contents

SYNOPSIS

       ls [OPTION]... [FILE]...

DESCRIPTION

       List information about the FILEs (the current directory by default).  Sort entries alphabetically   if none of -cftuvSUX nor --sort.

Mandatory arguments to long options are mandatory for short options too.

       -a, --all                             do not ignore entries starting with .

       -A, --almost-all                 do not list implied . and ..

       --author                             with -l, print the author of each file

       -b, --escape                       print octal escapes for nongraphic characters

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Installing Red Hat Enterprise Linux 5 Step by Step

1.    Power on your system. Press the appropriate key, typically ESC, F12, or DEL. If a boot menu isn’t available, you’ll need to adjust the boot sequence in the computer BIOS, which you can then use to boot directly from your selected media. Set your computer’s BIOS to boot from the first installation CD or USB drive. Details vary by PC. Make sure your BIOS saves your changes before you reboot.

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Redhat Enterprise Linux Text mode

You know you're in text mode when the whole screen is black, showing (in most cases white) characters. A text mode login screen typically shows some information about the machine you are working on, the name of the machine and a prompt waiting for you to log in:

RedHat Linux Enterprise Release 5.0 (Psyche)

blast login: _

The login is different from a graphical login, in that you have to hit the Enter key after providing your user name, because there are no buttons on the screen that you can click with the mouse. Then you should type your password, followed by another Enter. You won't see any indication that you are entering something, not even an asterisk, and you won't see the cursor move. But this is normal on Linux and is done for security reasons.

When the system has accepted you as a valid user, you may get some more information, called the message of the day, which can be anything. Additionally, it is popular on UNIX systems to display a fortune cookie, which contains some general wise or unwise (this is up to you) thoughts. After that, you will be given a shell, indicated with the same prompt that you would get in graphical mode.

Don't log in as root

Also in text mode: log in as root only to do setup and configuration that absolutely requires administrator privileges, such as adding users, installing software packages, and performing network and other system configuration. Once you are finished, immediately leave the special account and resume your work as a non-privileged user. Alternatively, some systems, like Ubuntu, force you to use sudo, so that you do not need direct access to the administrative account. Logging out is done by entering the logout command, followed by Enter. You are successfully disconnected from the system when you see the login screen again.

The power button

While Linux was not meant to be shut off without application of the proper procedures for halting the system, hitting the power button is equivalent to starting those procedures on newer systems. However, powering off an old system without going through the halting process might cause severe damage! If you want to be sure, always use the Shutdown option when you log out from the graphical interface, or, when on the login screen (where you have to give your user name and password) look around for a shutdown button.

Now that we know how to connect to and disconnect from the system, we're ready for our first commands.

Graphical Login mode in Linux

This is the default nowadays on most desktop computers. You know you will connect to the system using graphical mode when you are first asked for your user name, and then, in a new window, to type your password.

To log in, make sure the mouse pointer is in the login window, provide your user name and password to the system and click OK or press Enter.

Careful with that root account!

It is generally considered a bad idea to connect (graphically) using the root user name, the system.

Administrator’s account, since the use of graphics includes running a lot of extra programs, in root's case with a lot of extra permissions. To keep all risks as low as possible, use a normal user account to connect graphically. But there are enough risks to keep this in mind as a general advice, for all use of the root account: only log in as root when extra privileges are required.

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Characteristics or Properties of Linux

A lot of the advantages of Linux are a consequence of Linux' origins, deeply rooted in UNIX, except for the first advantage, of course:

Linux is free

As in free beer, they say. If you want to spend absolutely nothing, you don't even have to pay the price of a CD. Linux can be downloaded in its entirety from the Internet completely for free. No registration fees, no costs per user, free updates, and freely available source code in case you want to change the behavior of your system.

Most of all, Linux is free as in free speech

The license commonly used is the GNU Public License (GPL). The license says that anybody who may want to do so, has the right to change Linux and eventually to redistribute a changed version, on the one condition that the code is still available after redistribution. In practice, you are free to grab a kernel image, for instance to add support for tele transportation machines or time travel and sell your new code, as long as your customers can still have a copy of that code.

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Is Linux difficult?

Whether Linux is difficult to learn depends on the person you're asking. Experienced UNIX users will say no, because Linux is an ideal operating system for power-users and programmers, because it has been and is being developed by such people.

Everything a good programmer can wish for is available: compilers, libraries, development and debugging tools. These packages come with every standard Linux distribution. The C-compiler is included for free – as opposed to many UNIX distributions demanding licensing fees for this tool. All the documentation and manuals are there, and examples are often included to help you get started in no time. It feels like UNIX and switching between UNIX and Linux is a natural thing.

In the early days of Linux, being an expert was kind of required to start using the system. Those who mastered Linux felt better than the rest of the "lusers" who hadn't seen the light yet. It was common practice to tell a beginning user to "RTFM" (read the manuals). While the manuals were on every system, it was difficult to find the documentation, and even if someone did, explanations were in such technical terms that the new user became easily discouraged from learning the system.

The Linux-using community started to realize that if Linux was ever to be an important player on the

Operating system market, there had to be some serious changes in the accessibility of the system.

Linus and Linux

By the beginning of the 90s home PCs were finally powerful enough to run a full blown UNIX. Linus Torvalds, a young man studying computer science at the University of Helsinki, thought it would be a good idea to have some sort of freely available academic version of UNIX, and promptly started to code.

He started to ask questions, looking for answers and solutions that would help him get UNIX on his PC. Below is one of his first posts in comp.os.minix, dating from 1991:

From: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)

Newsgroups: comp.os.minix

Subject: Gcc-1.40 and a posix-question

Message-ID: <1991Jul3.100050.9886@klaava.Helsinki.FI>

Date: 3 Jul 91 10:00:50 GMT

Hello netlanders,

Due to a project I'm working on (in minix), I'm interested in the posix standard definition. Could somebody please point me to a (preferably) machine-readable format of the latest posix rules? Ftp-sites would be nice.

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Current application of Linux systems

Today Linux has joined the desktop market. Linux developers concentrated on networking and services in the beginning, and office applications have been the last barrier to be taken down. We don't like to admit that Microsoft is ruling this market, so plenty of alternatives have been started over the last couple of years to make Linux an acceptable choice as a workstation, providing an easy user interface and MS compatible office applications like word processors, spreadsheets, presentations and the like.

On the server side, Linux is well-known as a stable and reliable platform, providing database and trading services for companies like Amazon, the well-known online bookshop, US Post Office, the German army and many others. Especially Internet providers and Internet service providers have grown

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Which distribution should I install?

Prior to installation, the most important factor is your hardware. Since every Linux distribution contains the basic packages and can be built to meet almost any requirement (because they all use the Linux kernel), you only need to consider if the distribution will run on your hardware. LinuxPPC for example has been made to run on Apple and other PowerPCs and does not run on an ordinary x86 based PC. LinuxPPC does run on the new Macs, but you can't use it for some of the older ones with ancient bus technology. Another tricky case is Sun hardware, which could be an old SPARC CPU or a newer UltraSparc, both requiring different versions of Linux.

Some Linux distributions are optimized for certain processors, such as Athlon CPUs, while they will at the same time run decent enough on the standard 486, 586 and 686 Intel processors. Sometimes distributions for special CPUs are not as reliable, since they are tested by fewer people.

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Redhat Enterprise linux 5 VMware Installation part3

Redhat Enterprise linux 5 VMware Installation part2

Redhat Enterprise linux 5 VMware Installation part1

Linux in The Business

In 2008, IDC analyst Al Gillen cited a nearly 24 percent annual growth rate for the Linux industry, which puts a $21 billion 2007 technology at $49 billion in 2011. The companies involved in Linux include industry leaders such as IBM, Fujitsu, Hewlett-Packard, Oracle, Intel, Hitachi, NEC, and Novell. All have all invested time, talent, and resources to bettering Linux on their own and through the Linux Foundation.

If Linux is free of cost, how does a Linux company generate revenue?

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Linux Development

Linux is an operating system that is comprised of many different development languages. A very large percentage of the distributions' code is written in either the C (52.86%) or C++ (25.56%) languages. All of the rest of the code falls into single-digit percentages, with Java, Perl, and Lisp rounding out the rest of the top 5 languages.

The Linux kernel itself has an even more dominant C presence, with over 95 percent of the kernel's code written in that language. But other languages make up the kernel as well, making it more heterogenous than other operating systems.

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Linux in Community

Linux communities come in two basic forms: developer and user communities.

One of the most compelling features of Linux is that it is accessible to developers; anybody with the requisite skills can improve Linux and influence the direction of its development. Proprietary products cannot offer this kind of openness, which is a characteristic of the free software process.

Developer communities can volunteer to maintain and support whole distributions, such as the Debian or Gentoo Projects. Novell and Red hat also support community-driven versions of their products, openSUSE and Fedora, respectively. The improvements to these community distros are then incorporated into the commercial server and desktop products from these companies.

The Linux kernel itself is primarily supported by its developer community as well and is one of the largest and most active free software projects in existence. A typical three-month kernel development cycle can involve over 1000 developers working for more than 100 different companies (or for no company at all).

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Redhat Licensing

Code is contributed to the Linux kernel under a number of licenses, but all code must be compatible with version 2 of the GNU General Public License (GPLv2), which is the license covering the kernel distribution as a whole. In practice, that means that all code contributions are covered either by GPLv2 (with, optionally, language allowing distribution under later versions of the GPL) or the three-clause BSD license. Any contributions which are not covered by a compatible license will not be accepted into the kernel.

Copyright assignments are not required (or requested) for code contributed to the kernel. All code merged into the mainline kernel retains its original ownership; as a result, the kernel now has thousands of owners.

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