$ sudo apt-get install nfs-kernel-headersOn Fedora
$ sudo yum install nfs-utils system-config-nfsRead more ...
By creating a Logical Volume snapshots you are able to freeze a current state of any of your logical volumes. This means that you can very easily create a backup and once needed rollback to a original logical volume state. This method is very similar to what you already know from using Virtualization software such as Virtualbox or VMware where you can simply take a snapshot of entire virtual machine and revert back in case something went wrong etc. Therefore, using LVM snapshots allows you to take a control of your system's logical volumes whether it is your personal laptop or server. This tutorial is self-contained as no previous experience with Logical Volume Manager is required.
In this article we will explain how to manually create and restore logical volume snapshots. Since we do not assume any previous experience with Logical Volume Manager we will start from a scratch using a dummy physical hard drive /dev/sdb with size of 1073 MB. Here are all steps in nutshell:
One of the essential reflexes every new Linux user must develop is the reflex to search for information when something's amiss. But despite the fact that we live in a connected world, with search engines, wikis and huge quantities of information at our fingertips, it's always good to have the info we need already installed on the system we're working on. This makes for easy and fast access, and also for higher availability, should we lack access to an Internet connection. Besides, one can't always trust what one finds on the Web, and the manual pages are available in a consistent form, ready to answer questions to the impatient. One of the design philosophies standing behind Unix, and by inheritance Linux as well, is that the system should be well documented. This is how man pages came into being. While all Unix-based OSs have man pages, there are differences between them, so what works on Linux might not work on Solaris, for example. There is an issue, though: the writing style of these pages is terse, minute, impatient to the newcomer, so you might want to read a manpage a few times until you get accustomed.Read more ...
Although you may think that you have learned to master Linux command line with bash shell, there are always some new tricks to learn to make your command line skills more efficient. This article will teach you a few more basic tricks on how to make your life with the Linux command line & bash more bearable and even enjoyable.
This section will mostly deal with bash shortcuts in combination with three bash history expansion characters "!", "^" and "#". Bash Command History Expansion character "!" indicates start of history expansion. The "^" is a substitution character to modify a previously run command. The last optional character is "#", which denotes the reminder of the line as a comment.
$ echo Bash Shortcuts
echo Bash Shortcuts
!! is probably the easiest and most popular bash shortcut, which simply shows and executes your last entered command.Read more ...
Steganography is the art of hiding messages within other messages or data. Most commonly we see this utilized with pictures. This is probably encryption at its finest.
Mostly because it doesn't look like usual garbled text that we are used to seeing with encryption. The changes made by Steganography are so slight the human eye cannot perceive them. Even trained cryptographers may have an encoded message inside a picture and be unaware of it. There is a very deep science to this. Usually this is done by flipping parity bits at the binary level. While it is great to learn how this works, sometimes it can be a very tedious job. Fortunately for us there is a tool that will take away most of the grunt work.
This article will deal with installation and configuration of WebDAV server on Ubuntu Linux. WebDAV stands for Web Distributed Authoring and Versioning and allows connected users the edit and share data online via the HTTP protocol. This makes WebDAV a popular choice for developers when combined, for example, with Subversion or OpenLink Virtuoso. WebDAV is supported by number of clients ranging from davfs2, which makes it possible to mount the WebDAV's data storage to include into the local filesystem. This can be done with the mount command to various GUI applications with the native WebDAV support such as Nautilus, konqueror, etc. Futhermore, in this guide we will combine WebDAV with the Apache2 server.
In this section I would like to describe a scenario used in this tutorial. WebDAV can be very flexible service, which allows for number of configuration settings and scenarios. In this WebDAV tutorial we will start with the simplest basic startup WedDAV configuration and from there we will build it up to fit more complex environment. You can think of WebDAV as a HTTP extension for your existing website configuration. Normally, you may already have your apache website up and running. Thus, in that case, all you need to do to in order to include the WevbDAV service is to:
However, in this guide we will start from scratch starting from apache2 installation, virtual host creation, etc. Therefore, feel free to skip to any section most appropriate to your configuration requirement.Read more ...
Every system administrator I know develops in time the habit of putting together a toolbox where, as time passes, many useful pieces of software get added up, as the recurrent need arises. Please do not imagine this in the most classical of the sense, as this is not about a carpenter's toolkit, nor a mechanic's toolbox. It usually is a CD portfolio with live CDs, installable most-used distributions, vendor-specific tools and whatever not. Of the (indispensable) live CDs, one usually sees in the aforementioned toolbox a disk cloning item. What does it do? It helps a tremendous amount when you need to save and restore a hard disk, operating system included, and by save I mean 1/1 copy with the possibility of restoring in a few minutes, despite the ever-increasing size of the hard drives offered by the market today, where the terabyte becomes more and more common.
Such software exists, and indeed it makes the lives of admins and users alike much easier and efficient. Unfortunately, companies tried to impose their own proprietary disk image formats, so that restoring could be possible only by using their tools. Fortunately, there is a FOSS solution that deals with this, offering a very efficient live CD and server for download, and that is Clonezilla, which we'll talk about today. You are expected to have some knowledge on how disks work, networking and system administration. We will treat more advanced subjects a bit later on, but all you need to know if you are a beginner in those matters is right here.Read more ...
As a Linux system administrator you will be required to manage user accounts. This can be done by adding or removing user logins or simply by temporarily or permanently disabling an entire account while leaving the user's profile and files intact. This article describes a few ways on how to disable the user account in the Linux operating system.
The easiest way to disable the user account is to modify a /etc/shadow file, which is responsible for holding encrypted passwords for users listed /etc/passwd. Here is a typical user entry found in the /etc/shadow file:
tester:$6dKR$Yku3LWgJmomsynpcle9BCA:15711:0:99999:7:::Read more ...
Any decent Linux distribution comes with an installation option to automatically encrypt user's home directory. In case you do not wish to encrypt the entire home directory or perhaps you wish to encrypt some random directories on your Linux system you can use EncFS the FUSE-based cryptographic filesystem. EncFS will allow you to encrypt and decrypt any directory in a matter of seconds. It will reside on top of your current filesytem and provide access to any EncFS encrypted directory only upon entering a correct predefined password. This short tutorial will show you how to encrypt and decrypt your directories with the EncFS cryptographic filesystem.
Let's assume that you are a heavy Laptop user traveling from one place to another. You also use ssh quite often and so you have generated ssh keypair. For your convenience you even generated a private key without using a pass-phrase ( never good idea ). Furthermore, you have copied you public ssh key to multiple servers for an easy access. The problem with this scenario is that once someone gets hold of your Laptop s/he gets instantly access to all servers using you private ssh key. In this article we will show you how to encrypt your .ssh directory and avoid such problem.Read more ...