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.
Bash Command History Expansion
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.
Repeat last command
$ 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 ... WARNING: This process will erase all information from the Chromebook hard drive. As with all firmware flashes, there is a chance of something going wrong, rendering the device useless. Proceed at your own risk.
Chromebooks are everywhere. Google’s little Linux based PCs have been booming since their introduction several years ago in everything from homes to businesses, and even educational settings. Many users, especially Linux users, can’t get past the fact that the devices are hopelessly hamstrung by their ChromeOS operating system which both cuts down on the number of apps the device can run and makes it dependent on an Internet connection to get anything done.
So, what does a Linux user believing in the potential of their little (sort of)Linux laptop do? Break everything Google did. In many cases, Chromebooks are supported by the FOSS Coreboot project, meaning that there is a completely unlocked, free and open source version of the Chromebook BIOS just waiting to be installed. With a few relatively simple steps, that \$300 Chromebook can become a full fledged Linux laptop running just about any distribution. It should be noted that you should check which type of processor your Chromebook is running first, this method only supports Intel based Chromebooks. Another thing to keep in mind before getting started is that there are a ton of different Chromebooks. This method was tested with the extremely common Acer 7XX series, but it should work(maybe with subtle differences) on other Chromebooks as well.
Read more ... March 12, 2013
by Lubos Rendek
Whether you are administrating a small home network or an enterprise network for a large company the data storage is always a concern. It can be in terms of lack of disk space or inefficient backup solution. In both cases GlusterFS can be the right tool to fix your problem as it allows you to scale your resources horizontally as well as vertically. In this guide we will configure the distributed and replicated/mirror data storage. As the name suggests a GlusterFS's distributed storage mode will allow you to evenly redistribute your data across multiple network nodes, while a replicated mode will make sure that all your data are mirrored across all network nodes.
What is GlusterFS
After reading the introduction you should have already a fair idea what GlusterFS is. You can think of it as an aggregation service for all your empty disk space across your whole network. It connects all nodes with GlusterFS installation over TCP or RDMA creating a single storage resource combining all available disk space into a single storage volume ( distributed mode ) or uses the maximum of available disk space on all notes to mirror your data ( replicated mode ). Therefore, each volume consist of multiple nodes, which in GlusterFS terminology are called bricks.
Although GlusterFS can by installed and used on any Linux distribution, this article will primarily use Ubuntu Linux. However, you should be able to use this guide on any Linux Distribution like RedHat, Fedora, SuSe, etc. The only part which will be different will be the GlusterFS installation process.
Furthermore, this guide will use 3 example hostnames:
- storage.server1 - GlusterFS storage server
- storage.server2 - GlusterFS storage server
- storage.client - GlusterFS storage client
Use DNS server or /etc/hosts file to define your hostnames and adjust your scenario to this guide.
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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.
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This article describes an installation of SysAid software on a Linux system using tomcat and Apache. SysAid is a commercial web-based help desk software and if you were thinking to install either its free or paid version in your organization this guide should help you to achieve it. The default installation of SysAid IT help desk is quite very straight forward. On top of this basic installation this guide will provide you with some extra settings on how to configure SysAid with apache's https service using AJP proxy.
At first, we will perform basic Sysaid ROOT context installation using tomcat. After that we will combine this default Sysaid installation with mysql database and apache2 on port 80. Next we will create a self-signed SSL certificate and deploy sysaid to be accessible via HTTPS URL on port 443.
Here are listed basic environment attributes used in this guide:
- operating system Debian 6.0
- mysql 5.1, apache 2.2, tomcat 6
- example installation URL helpdesk.linuxcareer.com
The following command will fetch all prerequisites for a Sysaid installation on Debian Linux server. Please alter below packages to fit your RPM Linux system such as Fedora, Redhat, Suse and etc.
# apt-get install apache2 tomcat6 mysql-server sun-java6-jre
Debian users only:
If you get a message "Package 'sun-java6-jre' has no installation candidate" make sure to add non-free debian repository into your /etc/apt/sources.list. The following 2 lines below should do the trick:
# sed -i 's/main/main non-free/g' /etc/apt/sources.list
# apt-get update
Set default Java environment
It is possible that your system is running a OpenJDK java environment. Feel free to test this installation using your free OpenJDK java version or set the default java environment to Sun's Java(TM) SE Runtime Environment with:
# update-java-alternatives -s java-6-sun
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