Linux Training Online – Using the Linux CD Command to Change Directory – Linux System Administration

As a new user looking for Linux training, you need to learn how to use commands. And one of the most commonly used file system commands is the CD (change directory) command.

Using the Linux CD Command

The CD (change directory) command is used to change from your current directory (folder) into a different directory.

You need to change into a directory to do Linux administration tasks like:

  • create a new file or remove an existing file
  • copy or move a file to a different directory
  • edit and modify a file, such as a text configuration file for a Linux server
  • create a new directory or remove an existing directory
  • copy or move a directory to a different directory

Linux Commands Training Tips: The System Administration commands, examples and concepts covered here apply to ALL Linux distributions, including: Red Hat, Fedora, Ubuntu, Edubuntu, Kubuntu, Slackware, Debian, SUSE and openSUSE.

Linux CD Command Example – Changing into a Directory Below the Current Directory

To change directory into a directory “below” the current one, you type in CD and a space and the name of the directory you want to change into.

For example, to change into a directory named “letters”, you run the following:

$ CD letters

To change into a different directory, just replace “letters” with a different name.

Linux Training Tips: A directory inside the current one is considered “below” the current directory, and is called a sub directory.

Linux CD Command Example – Changing Up One Directory (Level)

To change directory up one directory (level), you type in CD and a space and then two dots (periods).

For example, if you have moved into the directory named “letters” and want to go back (up) to your previous directory, you run the following:

$ CD ..

Linux Training Tips: The directory above the current one is also called the “parent”.

Beyond This “Linux Training Online” ArticleThe Linux CD command is used in many other ways to navigate around the file system.

To continue your Linux training, you also need to learn how to use the CD command to: change to the root directory, change using an absolute path, and also easily change into a directory parallel to the current directory.

You can clearly and easily see all of the concepts and commands shown above (and lots more!) by watching a Linux training video.

With this method of Linux training, you can see how to use a command step-by-step and also hear how to run the command. This is a very easy way to learn how to use Linux.

Distributing the Processing and Storage Function in Distributed Systems

In distributed system, multiple computers are connected on the network working together as a system. These computer are independent but their collection appears to it users as a single coherent system. Distributed system provides sharing of resources and information. Processes executed on these systems can communicate with one another by exchanging messages over communication channel.

The distributed processing refers to LAN designed so that a single program can run simultaneously at various sites. Most distributed processing systems contain sophisticated software that detects idle CPUs on the network and parcels out programs to utilize them.

Another form of distributed processing involves distributed database, databases in which the data stored across two or more computer systems. The database system keeps track of where the data is so that the distributed nature of the database is not apparent to users.

A distributed database consists of two or more data files located at different sites on a computer network. Because the database is distributed, different users can without interfering with one another. However, the DBMS must periodically synchronize the scattered database to make sure they all have consistent data.

The software system that facilitates the the management of a DDB in such a way that the distribution aspects are transparent to users.

A DDBMS running on a different computer at each site can handle local applications autonomously and participates in at least one global application requiring data from other sites. Communication between different sites via a network is essential for any global application.

The Functions of Such DDBMS are:

To extend communication services to provide access to remote sites and allow the transfer of queries and data across the network.
To extend the DD to store data distribution details.
To provide distributed query processing, including optimization and remote data access.
To extend accuracy control to maintain consistency of replicated data.
To extend recovery services to take account of failures either of sites or of communication links.

Distributed data storage:

There are two approaches for storing data in distributed database.

Replication: The system create different similar copy of any data and each copy is stored on different places. There are two types of replication strategy.
Selective Replication
Complete Replication

Complete Replication: The complete replication strategy consists of maintaining a complete copy of the database at each site. This maximizes accessibility and reliability, but costs of storage and the communications needed for updates may be high.

MCSE Distributed File System

A Distributed File System (DFS) is a file structure that facilitates sharing of data files and resources by means of consistent storage across a network. The earliest file servers were designed in the 1970s. Following its inception in 1985, Sun’s Network File System (NFS) eventually became the foremost commonly used distributed file system. Aside from NFS, significantly distributed file systems are Common Internet File System (CIFS) and Andrew file system (AFS).

The DFS or Microsoft Distributed File System is an arranged client and server solution that enable a large organization to manage numerous allocated shared file within a distributed file system. It delivers site transparency and redundancy to enhance data accessibility in the midst of a breakdown or extreme load by permitting shares in a number of various locations to be logically arranged under a DFS root or a single folder.

It is a client/server-based service that permits individuals to directly access and process files located on the hosting server as if it had been on their personal computer. Every time an individual access a data on the server, the server transmits a copy of the data file, which is cache on the user’s personal computer while the information is being processed which is subsequently returned to the server.

Whenever individuals attempt to gain access to a share found off the DFS root, the individual is actually going through a DFS link allowing the DFS server to automatically re-direct it to the appropriate share and file server.

There can be two methods for utilizing DFS on a Windows Server:

A Standalone or Distinct DFS root provides you with a DFS root found only on the local computer, which therefore does not make use of Active Directory. A Standalone DFS can only be accessed on the local PC where it was made. It does not feature any kind of fault tolerance and could not be connected to any other DFS.

Domain-based DFS roots can be found within Active Directory which enables you to have their information and facts distributed to any number of domain controllers located in the domain; this provides you with fault tolerance to DFS. DFS roots that can be found on a domain needs to be hosted on a domain controller. This is to make sure that links with identical target get hold of all their duplicated data through the network. The file and root data is replicated by means of the Microsoft File Replication Service (FRS).

Advantages of DFS

1. Easy accessibility: individuals do not need to be aware of various locations from where they acquire data. Simply by remembering a single location they will have access to the data.

2. Fail Tolerance: for master DFS hosting server it is possible to obtain a duplicate (Target) on yet another DFS Server. With the help of the master DFS server end users are still able to continue on accessing the data from a back-up DFS (Target). There is absolutely no interruption in being able to access information.

3. Load Balancing: in the event that all of the DFS root servers and targets are operating in good condition, it results in Load balancing. This is often accomplished by indicating locations for different users.

4. Security and safety: By making use of the NTFS configuration, security is put into practice.