Content management system

A content management system (CMS) is a computer application used to create, edit, manage, and publish content in a consistently organized fashion. CMS are frequently used for storing, controlling, versioning, and publishing industry-specific documentation such as news articles, operators’ manuals, technical manuals, sales guides, and marketing brochures.

* Joomla   * osCommerce   * Smarty   * Drupall   * WordPress

What is Telnet

Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. Through Telnet, an administrator or another user can access someone else’s computer remotely. On the Web, HTTP and FTP protocols allow you to request specific files from remote computers, but not to actually be logged on as a user of that computer. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific application and data on that computer.

 Example telnet commands: 

Connect to a remote system       telnet> open remote_system_name

Suspend a telnet connection      Ctrl ]
and return to the telnet
prompt

Close a connection to a                   Ctrl ]
remote system                                telnet> close

**Suspend telnet and work on     telnet> z
the local system

**Resume the use of telnet  prompt% fg
                                 telnet>

End the telnet session           telnet> quit

To display a list of telnet      telnet> ?
commands

To get an explanation of a       telnet> help name_of_command
command

What is Linux

Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world. Developed under the GNU General Public License , the source code for Linux is freely available to everyone.

In the narrowest sense, the term Linux refers to the Linux kernel, but it is commonly used to describe entire Unix-like operating systems (also known as GNU/Linux) that are based on the Linux kernel combined with libraries and tools from the GNU Project and other sources. Most broadly, a Linux distribution bundles large quantities of application software with the core system, and provides more user-friendly installation and upgrades.

Initially, Linux was primarily developed and used by individual enthusiasts. Since then, Linux has gained the support of major corporations such as IBM, Hewlett-Packard, and Novell for use in servers and is gaining popularity in the desktop market. Proponents and analysts attribute this success to its vendor independence, low cost, security, and reliability.

System Directories

comman system directories

• /bin – Used to store user commands. The directory /usr/bin also stores user commands.
• /sbin – Location of many system commands, such as shutdown. The directory /usr/bin also contains many system commands.
• /root – The home directory of the superuser.
• /mnt – This directory typically contains the mount points for filesystems mounted after the system is booted.
• /boot – Contains the kernel and other files used during system startup.
• /lost+found – Used by fsck to place orphaned files (files without names).
• /lib – Contains many library files used by programs in /bin and /sbin. The directory /usr/bin contains more library files.
• /dev – Stores device files.
• /etc – Contains many configuration files and directories.
• /var – For “variable” files, such as log files and the printer spool.
• /usr – Contains files and directories directly relating to users of the system.
• /proc – A virtual file system (not actually stored on the disk) that contains system information used by certain programs.
• /tmp – A “scratch pad” for users and programs. /tmp has global read/write access.
• /home – Typical location of user home directories.

File permision

Every file or folder in Linux has access permissions. There are three types of permissions (what allowed to do with a file):

• read access
• write access
• execute access

Permissions are defined for three types of users:

• the owner of the file
• the group that the owner belongs to
• other users

Thus, Linux file permissions are nine bits of information (3 types x 3 type of users), each of them may have just one of two values: allowed or denied.

Textual Represntation

It is used in Linux long directory listings. It consists of 10 characters. The first character shows the file type. Next 9 characters are permissions, consisting of three groups: owner, group, others. Each group consists of three symbols: rwx (in this order), if some permission is denied, then a dash “-” is used instead. Example:

-rwxr--r-- 0123456789

• Symbol in the position 0 (“-”)is the type of the file. It is either “d” if the item is a directory, or “l” if it is a link, or “-” if the item is a regular file.
• Symbols in positions 1 to 3 (“rwx”) are permissions for the owner of the file.
• Symbols in positions 4 to 6 (“r–”) are permissions for the group.
• Symbols in positions 7 to 9 (“r–”) are permissions for others.

r————– Read access is allowed

w————- Write access is allowed

x————- eXecute permision is allowed

Examples:

-rwxr-xr-x	File, owner has read, write, execute permissions, group: only read and execute permissions, others: only read and execute permissions.
dr-x------	Directory, owner has read and execute access, group and others have no access

Apache http server

The Apache HTTP Server, commonly referred to simply as Apache, is a web server notable for playing a key role in the initial growth of the World Wide Web. Apache was the first viable alternative to the Netscape Communications Corporation web server (currently known as Sun Java System Web Server), and has since evolved to rival other Unix-based web servers in terms of functionality and performance.

How to access pen drive in linux

Open vi editor type below the commands 
Command:
mkdir /mnt/pendrive
mount -t vfat /dev/sda1 /mnt/pendrive

where vfat is the type and sda1 is the dev for your drive.
the -t vfat is not allways nessisary but if it mounts and you have
read or write errors then you need the -t vfat.
Well hopefully this helps someone. Oh don’t forget to unmount using
umount /mnt/pendrive
Where /mnt/pendrive is the mount point.  If you dont unmount you will
loose changes and risk missing up your partition.

now u access pen drive happily

FTP Commands

Comman FTP Cmmands

?	to request help or information about the FTP commands
ascii	to set the mode of file transfer to ASCII (this is the default and transmits seven bits per character)
binary	to set the mode of file transfer to binary (the binary mode transmits all eight bits per byte and thus provides less chance of a transmission error and must be used to transmit files other than ASCII files)
bye	to exit the FTP environment (same as quit)
cd	to change directory on the remote machine
close	to terminate a connection with another computer
	close brubeck	closes the current FTP connection with brubeck,   but still leaves you within the FTP environment.
delete	to delete (remove) a file in the current remote directory (same as rm in UNIX)
get	to copy one file from the remote machine to the local machine
	get ABC DEF	copies file ABC in the current remote directory to (or on top of) a file named DEF in your current local directory.
	get ABC	copies file ABC in the current remote directory to (or on top of) a file with the same name, ABC, in your current local directory.
help	to request a list of all available FTP commands
lcd	to change directory on your local machine (same as UNIX cd)
ls	to list the names of the files in the current remote directory
mkdir	to make a new directory within the current remote directory
mget	to copy multiple files from the remote machine to the local machine;   you are prompted for a y/n answer before transferring each file
	mget *	copies all the files in the current remote directory to your current local directory, using the same filenames. Notice the use of the wild card character, *.
mput	to copy multiple files from the local machine to the remote machine;   you are prompted for a y/n answer before transferring each file
open	to open a connection with another computer
	open brubeck	opens a new FTP connection with brubeck;   you must enter a username and password for a brubeck account       (unless it is to be an anonymous connection).
put	to copy one file from the local machine to the remote machine
pwd	to find out the pathname of the current directory on the remote machine
quit	to exit the FTP environment (same as bye)
rmdir	to to remove (delete) a directory in the current remote directory

What is samba server?

Samba is a protocal by which a lot of PC-related machines share files and printers. Samba is a strong network service for file and print sharing that works on the majority of operating systems. When well implemented by the administrator, it’s faster and more secure than the native file sharing services available on Microsoft Windows machines.

These are the Package(s) required:
download:samba-2.0.7.tar.gzSamba Homepage: http://us1.samba.org/samba/samba.html

What is iptabels?

iptables

iptables is the userspace command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators.Since Network Address Translation is also configured from the packet filter ruleset, iptablesis used for this, too.The iptables package also includes ip6tables. iptables is used for configuring the IPv6 packet filter.

ip6tabels

The introduction of the next-generation Internet Protocol, called IPv6, expands beyond the 32-bit address limit of IPv4 (or IP). IPv6 supports 128-bit addresses and, as such, carrier networks that are IPv6 aware are able to address a larger number of routable addresses than IPv4.

Red Hat Linux supports IPv6 firewall rules using the Netfilter 6 subsystem and the IP6Tables command. The first step in using IP6Tables is to start the IP6Tables service.

Command: 
service iptabels  start

service iptabels off 
chkconfig iptabels off