Ruby, The OOP language of the future


Ruby is AWESOME.

Yes thats right awesome. Ruby is a language that is both simple and powerful. It is completely object orientated, where everything that you work with is an object. That is numbers, strings, data structures and any program construct that you can think.

Created in japan by Yukihiro “matz” Matsumoto and released in 1995, It has since grown into a widely used langauge, in the top 10 listed languages on github project language page. This is mostly due to the natural order of programming, having a limited amount of clutter.

Ruby is also an interpreted language. We will go into this more later, but essentially means that it runs inside a special program that is built to take the ruby code and execute it. It is not necessarily the fastest interpreted languages, but it is one of the most powerful. There is a number of different interpreters, invoking different mechanisms and built in different languages (the major ones are c and java). This allows the user to implement different interpreters depending on the execution environment.

Lets look at some code, how about a hello world program. But first we need to install ruby on our machine. For ubuntu and fedora the code for installation is as follows.

sudo apt-get install ruby1.8 rubygems1.8

yum install ruby.i386 ri.i386 ruby-mode.i386

Now create a file named helloworld.rb and put the following line on the first line.

puts "Hello World!"

Yep thats it. Run it in the command line by using ruby helloworld.rb and it will output will be the string Hello World! This ease of use is due to mostly to the number of executed lines of per line of ruby code, averaging around 15 per ruby line.

Before continuing on with more examples, finishing of this post on ruby will be about ruby on rails, the new web programming application which comes inbuilt with its own web server and many other features.

Rails as its collectively known, was released to the public in 2003 by David Heinemeier Hansson, although now is actively developed by a team of 1600 community developers lead by a core team. The core concept behind rails is that it allows you to right the beautiful code of your ruby apps, in a web environment.

Thats about all for a first introduction of ruby, next time i will show you how to set up a working environment for deploying ruby on your machine (Linux first and then windows and mac). Why not read up on the ruby programming language.

Quick Tip – Connecting to Another Machine (Linux to Linux)


In todays quick tip I will discuss methods of connecting to another computer. There are many different methods of doing this, even more if you want to mix and match between Windows, Mac OSX and Linux. Today I will just be looking at a Linux to Linux connection.

First off, for today I am going to be connecting to a system that I built for my parents (details of the build to come) to grab a few photographs that my dad took on his latest holiday. They have a central Linux system with a file server through port forwarding on port number 400.

The first method to connect is via a simple ssh shell command

ssh dad@X.X.X.X -p 400

Where dad is my dads username, X.X.X.X is his IPv4 address and -p 400 says that i want to connect on port 400 which will tell the router at my dads house that I actually want to talk to the file server. What I have now is a connection to file server and access to everything on that local machine, with the input output information sent to my machine.

So what can i do with this. Funnily enough, this simple command is powerful if you want to use the remote computer. You can run an update, run any command line program (cat /etc/passwd :P) or execute shell scripts to achieve tasks like backup or batch file manipulation. To copy files between computers we are going to need another command.

At this point we have three different options, two command line choices and one GUI, (the GUI only needs your computer to have the GUI not the remote computer.

scp dad@X.X.X.X:400/home/dad/image.jpg /home/me/image.jpg

or

sftp dad@X.X.X.X:400
get /home/dad/image.jpg

or

Places -> connect to server -> Fill out needed information -> connect
enter password -> navigate through window to file -> drag and drop to desired location

The first option is my favorite and the most simple command if you know exactly what you want and where you want to put it. The first part logs onto the ssh server and locates the file for copying, and the second part says where the file should be put. While it is simple, it has no margin of error, it either works or doesn’t, and can do some squiggly things.

The second option is the best for looking for and finding files without a GUI. You must first login to the ssh server in ftp mode and then find and “get” (download) the file. I don’t really use this option often, but it’s handy to know.

The third option is great if you want a graphical way of interacting file on an external server. This is very simple once you have seen what to do. Hopefully I will be able to do a quick video to show how to do this, which I will link at a later stage.

This outlines the way that you can connect to different Linux boxes on either you own subnet, or even over the internet. Stay tunned for more posts related to connecting computers, in particular mac and windows to linux connection.

Using APT – The Complete How to Guide


Debian’s APT (Advanced Packaging Tool) is an amazing program that adds greatest level of manipulability to the distributions that use it. It enables the user to control the software that runs on their computer, making it exactly the way they like it, without any extra programs that do not get used. This is unlike any other non-*nix operating system, giving A clear advantage, in my opinion, to it’s users.

Essentially APT is a front end to dpkg, a base level program for installing and removing and providing information about .deb packages. Going into depth of dpkg and .deb files is for another time, but briefly a .deb package is a way of puting a program into a container that makes it’s installation much simpler for the end user and dpkg was written for handling these packages.

APT is also able to use the RPM package management system, using the apt-rpm method (explained later). This is a newly acquired feature of APT which I believe that was added to make the Debian distribution POSIX compliant. RPM was created for the Red Hat Linux distribution as a simple package management system which has solid dependency handling.

Now APT is available on all Debian based distributions such as Ubuntu, Mint, Knoppix and a number of others, as well as Solaris (not open any more). This means that of all the users of Linux distributions, many have access to APT. Lets see the program in action. Open the terminal and enter the following

sudo apt-get update

To run the APT program you must run as a super user or provide super user privileges. You will also notice that there is the `tack get` addition of the apt program. This is because the program has many sub layers, with others such as apt-cache, apt- secure and apt-key. The update program updates the latest information from the sources list.

The sources list is the location of the Debian packaged programs that are installable via a direct download from apt-get. Finding the best sources for the apt-get program will be in a quick tip, for now we will assume that all the sources will be the optimal ones. Now lets perform a second command related to the sudo apt-get update command, upgrade

sudo apt-get upgrade

This command upgrades the current installed programs in a number of ways. First it checks to see if all the packages are the latest version of the installed programs. If there are new versions it does a dependency check and asks if you would like to update at which stage it will let you know of any other programs need to be installed. (hit enter here) It will then proceed to update and install until your current installed programs are how they should be at their newest version.

How about installing programs. Simple ! Just use the sudo apt-get install command. The trick is knowing exactly what program you need. For example, I am writing a program which works with a database in c. I need the mysql header files which are not installed by default. The trick with accessing header files is to download the development packages of the need programs so I used the following install command.

sudo apt-get install libmysqlclient-dev

These 3 main commands can handle 90% of your apt needs. Below is a list that i have compiled about commands and there functions that you may come across needing in your use of the program.

sudo apt-get remove `program`

This removes the installation of the program specified but still lives on the system

sudo apt-get autoremove

This automatically removes all the programs which are not being used and are not depended on by any other programs.

sudo apt-get clean

This cleans the archives of the downloaded programs. Any Archives that are not needed are removed, freeing up space.

sudo apt-get autoclean

This automatically removes the archives that are not needed and any dependencies as well

sudo apt-get source `program`

This downloads a source version (if available) that will need other install methods, in order to examine the source code and build specifically the way you choose.

deb `link` `version` `relationship`

This adds a source to the list. Link is source location, version is the word number of the version being used eg ubuntu uses “hardy” or your version equivalent and debian would use ‘lenny’ for v5 or ‘squeeze’ for v6. The relationship is a little more complex. Most likely it will be partner, But it may equally be universe or multiverse.

apt-cache search `program`

searches all repositories and list ever instance of the program. This is a great way to find a program that you are looking to download.

sudo apt-get dist-upgrade

This updates packages which have may have any number of dependency discrepancies.

This list is incomplete. Its a ‘working copy’ of the most commonly used apt commands. The important thing to remember is to run the update before you start working with apt so that you have the latest information, as well as anytime you add or remove sources.

If you have any questions or use any commands relating to apt that I haven’t listed, please let me know in a comment below.

Quick Tip – Man Pages


Linux Man pages are one of the most useful resources a Linux user has in his arsenal when it comes to learning about a command line functionality or just about anything you could need to know about Linux. For example, today I want to transfer some log files from my server to my main computer analysis but a small script I had written, I decided do this via ftp (just cause I could). So the first thing that I did was check the man page to ensure I used the correct commands, by using man ftp.

man ftp

This shows an interactive document. You can scroll down to read more, press q to exit.

There are many different sections to the man program, each containing a different subset of commands and programs. This allows for different documentation of similar or the same named programs. For example, the apt program has to expansions – annotation processing tool and advanced packaging tool. Usually typing in a command into man produces the output you want, sometimes though you have to go searching.

man apt

This gives the man page for annotation processing tool.

man 8 apt

This gives the man page for advanced packaging tool.

If you come across the someone else referencing a man page, or you yourself want to reference a man page you would write it man program(section) eg for advanced packaging tool you would use man apt(8)

Update – 3 new server tutorials


A while ago I wrote the first 2 tutorials on setting up a home server, and slated in for further release 3 more tutorials on hardware, burning an ISO and installing the base system. Well today they have been released.

Hopefully they work well, and no one falls into any traps following them. I intend to two follow these up with some more complex tutorials on user based management relating to specific tasks such as (the next one) creating users with default folder and files as well as git version control, creating a simple backing up process, working with a mail program and many others.

All the tutorials can be found linked on the build a home server page.

I look forward to your responses and would love to hear of your success/failure as well as any changes you feel need to be made.

Selecting Hardware for a Server – Ubuntu Server


Hardware is KEY.

You must have the BEST.

I am here to tell you that ITS ALL LIES. Fed to us through not just the media but big businesses and other corporate goons, bent on taking us for as much money as we can. The truth of the matter is that unless your running windows 7 ultimate packed full of processor heavy programs, you only need the most minimal of hardware setups by todays standards to run a server and even then it will most like be underused. (more…)

Installing the Base System – Ubuntu Server


Now we have the hardware, and the software setup and ready to go, we can begin the install. make sure that you have set up the hardware with all the peripherals attached.

Step 1

First we must enable the computers BIOS to load from the cd. To do that turn the computer on. Depending on the chip set of the computers motherboard there will be different keys for entering the BIOS setup. It is usually either F1, F2, del, esc, or F10. press one of these key before the computer loads the boot loader screen. Once into the BIOS you will want to find the boot load order. Once you have found the boot load setting, change the order so that the CD-DISK option (or similar) is number one.

exit and save from the BIOS screen and insert the install disk from Part 3.

Step 2

The computer will load into the disk. First it will ask for your language, Hit enter for the default (English) or select your preferred language. Next it will bring up a basic option list. Select the “install ubuntu server” option. This will then load an ncurses screen (blue white and red with monospace font). It will then as a for a number of options

  • Select your langauge
  • Select Your Location

You will now be asked whether you want to automatically select your keyboard. I have never had this work successfully, however you could give it a try, particularly if you have a non standard keyboard, otherwise select no.

If you pressed no and you have a standard keyboard it is a US keyboard. There will be 2 or 3 screens where you must select your keyboard. If you have a nonstandard keyboard, select your variation.

If you pressed yes you will have to press some keys and it will work out which keyboard you have. There will be multiple keys.

Step 3

After selecting your keyboard the installer will load a few additional component and then set up DHCP. This means it is looking for an Internet connection. If you do not have an INTERNET connection auto detection will fail and you will have to select “set up DHCP later” other wise it will auto configure and you should be able to move straight on.

If it fails and you have the server plugged in to the Internet there are a few simple things you can check. Make sure that if you have multiple Ethernet ports (multiple NIC’s), try changing the Ethernet cord to another port. Make sure that you actually can connect to the Internet on another computer (you should have another computer else you wouldn’t need to set up a home server).
You can also try manually setting up the DCHP setting, although that shouldn’t be necessary.

You will then need to set the host name. You can set this to what ever you like.

You will then be asked whether you the time zone detection has configured the correct zone, if it has not you will need to change it, otherwise hit enter.

Step 4

Now we have to setup the partitions. Select The Guided – use entire disk and setup LVM. You will then need to select which hard drive you want to use. Select the one that you want to install the primary operating system on. It must be no less than about 10GB, although for the best results from a home server 60 – 80 GB would be optimal (For there to be enough room to backup and store all of your important information.

Next select yes you would like to save the changes. The next screen will ask you for how much you would like to use for the / (root) and swap partitions. I suggest using no less than 20GB or 40 – 50% of the drive. This allows for expansion if necessary.

Save the Logical Volume Management and write the changes to disk.

Step 5

After the completion of Step 4, The system will be installed. At some point, you will be asked to enter a name for the new user. This is the main user that controls the server, they will have root access through the sudo command. You cannot call this user admin or root. I suggest entering your Name.

Next You need to enter the users username, I usually make this my first name or administrator. but it is up to you (you cannot use admin or root). You will then be asked for the users password. If you will be able to access the server from the Internet ie it servers web pages or has public ftp etc, you will need a strong password. Make it more than eight letters, with a mixture of numbers, lower and uppercase letters and if your frantic symbols as well. If you home server will never be accessible from the Internet then you can make the password as simple as you like (still suggest at least 4 letters).

The last two parts of step 5 are 1 – do you want to encrypt you home directory. The answer here should be no. unless you are storing sensitive data it won’t need to be encrypted and 2 – are you behind a proxy. Leave this blank unless you use a proxy server to connect to the Internet

You system will now start to install

Step 6

After a short period of time you will be asked whether you want to automatically update your system. You should manually do this for greater control, so select “No automatic updates”
Another short period of time later you will be asked what extra software you would like to install. I prefer to manually add extras software so I would hit enter, however if you would like the installer to automatically setup the system add which of the servers you would like it to setup by scrolling to the server and pressing space bar and hit enter when you are finished.

The installation is now nearly complete, all you have to do is hit yes when asked if you would like to add the grub boot loader to the master directory and then when prompted remove the cd and restart the computer.

Now you have installed the base ubuntu server.

Next we will add setup users and and user version control so that the files can be better managed.

Getting Ready to Install – Ubuntu Server


The Following article is suitable for any Linux Distribution, however make sure that there are no alternate instructions on the distribution you are using.

Now that we know which version of Ubuntu we are going to install we can prepare the installation disk. The first thing that we need to do is download the iso. The iso is an archive type formate that is burnable to a disk. It can be anything really, a dvd, a cd, a USB Thumb drive. The iso itself can be found many places. Primarily it can be downloaded from the main Ubuntu website. It can also be downloaded from a mirror. Google Ubuntu mirror and your country name will bring up many different mirrors, select a relevant one and navigate to and download the iso. I live in Australia and on a university campus so i use mirror.aarnet.edu.au from which i can download the whole iso (700MB) in 15-20 seconds.

Now we will need to load the iso onto the disk (for this article i will be putting it on a cd. I will go through all the different methods and OS later). Below is a list of descriptions for each primary operating system

  • Ubuntu
    1. Insert a blank disc. Cancel any pop up windows that may open
    2. Right click on the downloaded iso and choose the option “Write to Disc”
    3. Select the Write speed and location of write – either of theses options may not be available.
    4. Click Burn. The setup of the install disc is finished.
  • Mac
    1. Launch Disk Utility (Applications → Utilities → Disk Utility)
    2. Insert your blank CD/DVD
    3. Drag and drop your .iso file to the left pane in Disk Utility. Now both the blank disc and the .iso should be listed
    4. Select the .iso file, and click on the ‘Burn’ button in the toolbar
    5. Ensure that the ‘Verify burned data’ checkbox is ticked (you may need to click on the disclosure triangle to see the checkbox)
    6. Click ‘Burn’. The data will be burned and verified
  • Windows 7
    1. Right-click on an ISO image and choose ‘Burn disc image’
    2. Select a disk burner (drive) and choose ‘Burn’. If you check ‘Verify disc after burning’, it will confirm that the ISO image has been burned correctly

For a more comprehensive list of how to burn an iso visit BurningIsoHowto which details every way to burn disk image onto a any form of disk. Thank you Ubuntu.

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