Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *          63    39070079    19535008+  83  Linux
<strong>Partition 1 does not start on physical sector boundary.
</strong>/dev/sda2        39070080    46877669     3903795   82  Linux swap / Solaris
/dev/sda3   *    46877670   144536804    48829567+  86  NTFS volume set
<strong>Partition 3 does not start on physical sector boundary.
</strong>/dev/sda4       144536805  1250263727   552863461+  86  NTFS volume set
<strong>Partition 4 does not start on physical sector boundary.</strong>

I “shrinked” the original Windows 7 to 40 GB with Gparted live and created the partitions during the installation of ArchLinux with cfdisk so what’s wrong with these operations ?

The Problem is that the disk of Dell Latitude 6530 uses the Advanced Format Technology, in short

The ‘advanced format’ feature reduces overhead by using 4 kilobyte sectors instead of the traditional 512 byte sectors. The old format gave a format efficiency of 87%. Advanced Format results in a format efficiency of 96% which increases space by up to 11%. The 4k sector is slated to become the next standard for HDDs by 2014.

Great, so I should worry of this message ?
While looking around I found a very informative article on IBM website: Linux on 4KB-sector disks: Practical advice where you can find the following figure and much more information:

A value of 1.00 means no penalty; higher values mean worse performance.

Reading it I understood that In theory this sort of partitioning may affect read/write IO rates somewhat, depending on your drive’s firmware, as my installation was just finished I’ve preferred to scratch everything and re-partition the drive correctly.

So now the question is how to do it ?

First test: Gparted

I used my usb stick with Gparted Live to resize the partition that were affected by the problem, as the partitions are of some hundreds of GB this operation took around 15-20 minutes for each run, the idea was to leave some space before the partitions and align it to the disk -> Failed
I tried to set the option “align to cilinder” and in theory Gparted should be aware of disk geometry but in practice I was able to fix just 2 of my 4 partitions and also doing multiple tests I was unable to resize the partitions and align them.

So I decided to reinstall everything (with Arch it’s a good exercise anyway ) and be careful to create the partitions aligned from the start.
From ArchLinux wiki i see that the versions that supports this mode are:

• fdisk, since util-linux >= 2.15. You should start with ‘-c -u’ to disable DOS compatibility and use sectors instead of cylinders.
• parted, since parted >= 2.1.
• mdadm, since util-linux >= 2.15
• lvm2, since util-linux >= 2.15

So I’ve used fdisk with the option -c -u, so during the installation I run:

fdisk -c -u /dev/sda

And recreated all the partitions I need in my new Linux system, this time if I write fdisk everything is clean.

Perfect I can now complete my new ArchLinux installation.

Related posts:

1. Linux shell: Dfc – Check your disk space with style
2. How to play Minecraft on Archlinux

Some of the Linux faithful will look at this and say: “There he goes again, bashing open-source. He’s just a Microsoft shill.” They will use the fact I am an MCSE as ‘proof’ of their opinion.

Version 4.0 of LOO still suffers from the issue of cross file compatibility to Microsoft Office. However, the good news is the pain is less than ever before and we now get the ability to open Visio and Publisher files! Personally, I have not used either of these Microsoft programs in years so I cannot attest to how well they are handled.

Beyond my own daily use of LOO I have read in depth every review I could find on the Internet. My honest summary is they are far more negative than my feelings. Yes I must agree with everyone else that the most lacking area is complex documents not playing nice with MS Office. The second most cited shortcoming is the relatively confusing menus. I cannot really disagree there either. And there is always two sides to the coin. LOO’s brightside is shinier than ever. Less noticed is how much this version has pulled away to lead over Apache Open Office (AOO) formally known as Open Office Organization (OOO).
More about that later.



I’m not going to rehash what you can read in many dozens of other reviews. I will summarize with LLO runs faster than ever and is more compatible to Microsoft Office than ever. Instead let’s take a few minutes and focus on what LOO has done to get here and what it means for us tomorrow.

Java dependencies are being depreciated with either Python or native platform code. Given the security issues with Java, this is a good thing no matter what OS you use. This is one of several important trends for the sweet

The major flaw beyond file conversion has been this week could not handle content management in a large organization. It now adheres to a CMIS standard http://en.wikipedia.org/wiki/CMIS.

Large organizations have this barrier removed in the latest incarnation. Little noticed is the solution for reducing pagination issues with Microsoft Office easily handled by not using Microsoft specific fonts. Another former no removed is it can now import ink annotations from Word. Comments can now be attached to document text ranges. Another improvement is allowing a different header and footer on the first page without requiring a separate page style.
Perhaps these are really specific things, but if you work with documents every day they are really important for your work and the look of your document.

Some people will like the fact that the PowerPoint work alike called Impress has a Remote Control App for Android.

Through all this there is a point I believe all the reviews have missed. It is my belief that the full measure of time will show that Libre Office Version 4 was the pivot point for this offering to really move into the mainstream. Certainly all the improvements I mentioned (and many more commented on elsewhere) are factors.

What I don’t see it mentioned anywhere is The Document Foundation has registered in Berlin a Stiftung. This is a standard supervised by the German authorities with a history dating back to the year 1509. This gathered immediate support from major industry players showing that they are really in it for the long haul.

Backing this up is the fact that this is the year we see the first group of folks who will be blessed under the Certification Program for LibreOffice.

I know I am going to upset the Linux faithful. While this group wants mass-market acceptance, it also wants everything to be freedom of choice. And this is exactly why Open Source fails to win significant mind share.

Large organizations must have standards. It is the only way humans can handle large numbers without chaos. Senior management in large organizations looked for large organizations that had standards. Beyond knowing this was a requirement for them to get on with business, they also knew they had someone to sue if those standards were not met. And this is where open source has failed them.

Now having an international standards body deeply rooted in history, rapid yet orderly improved interoperability and CMS, LLO has set the stage to move into: The Limelight.

Today AOO/OOO has a larger installed base then LOO. That will change quickly. While both use ODF, not all ODA’s are equal. Monitoring the AOO list as I do, I found a case in point. A user was having an issue they were trying to solve. I cannot say the AOO group was unhelpful. They were in fact very kind and supportive. And it showed yet another way how LOO is pulling ahead.

“ODF has a flat file format without container too. This is implemented in LO but not in AOO. But in the flat format all pictures are stored in base64, because there is no folder to store them in original format.”

It has always been a long-standing feature of both Open Source office platforms that they could resurrect data from long abandoned platforms including Microsoft formats the company did not support in its own programs. And being free certainly did not hurt.

I want to conclude with a thought for my fellow MCSE’s. The IT department budget is always getting squeezed. Prior to LO V4, you just did not have the support to run the size of an operation you do. LO has given you the tools to make a solid business case. Just get away from the MS centric fonts when you’re doing your proof of concept.

Related posts:

1. Ekiga and SIP to replace Skype
2. Windows vs Linux Software

Thanks to all the Indie games, Steam and Humble Bundle recently the market of games for Linux has become most active than ever and so I’ve bought some arcade/action/platform games.

Perhaps it’s just me but I don’t like too much to manage around 10 different keys on the keyboard and remember all the combo that I’ve to do with them, a joypad it’s a much simpler way to play that kind of games, and what’s the best joypad around ?

In my opinion Playstation joypads are some of the best you can find around, probably Xbox are good too, but I’ve an unused playstation 2 and so I’ve choose to go in that direction.

And I must say that with a great surprise everything worked fine without too much problems !!

Please note I’ve tested this on my Linux Mint 14, that uses the same Kernel (3.5.x) and software of an Ubuntu 12.10.

Playstation 2 to USB adapter

As first thing you have to buy an adapter from the Playstation 2 joypad to a standard USB port.
I’ve bought the following model from Ebay for 3€, I’ve choose this for 2 reasons:

• It’s really cheap
• It can be used to plug in 2 joypads

Once plugged in your linux box run from a terminal the command lsusb, you should see an output like this one:

mint-desktop tmp # lsusb
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0951:1643 Kingston Technology DataTraveler G3 4GB
Bus 001 Device 004: ID 058f:6364 Alcor Micro Corp. AU6477 Card Reader Controller
Bus 002 Device 003: ID 0424:2524 Standard Microsystems Corp. USB MultiSwitch Hub
Bus 002 Device 004: ID 2001:3c19 D-Link Corp. DWA-125 Wireless N 150 Adapter(rev.A3) [Ralink RT5370]
<strong>Bus 002 Device 009: ID 0810:0001 Personal Communication Systems, Inc. Dual PSX Adaptor
</strong>Bus 002 Device 006: ID 050d:3201 Belkin Components F1DF102U/F1DG102U Flip KVM
Bus 002 Device 008: ID 046d:c01d Logitech, Inc. MX510 Optical Mouse
Bus 002 Device 007: ID 046d:c315 Logitech, Inc. Classic New Touch Keyboard

This means that so far is all good.

Test the Joypad within Linux

Connect the joipad of your Playstation 2 to the adapter, now how you can test it ?
A software that does this work is jstest, so install the package that contains it with the command:

sudo apt-get install joystick

Or equivalent if you are not using a .deb Linux distribution.
Now you can run the following command from a terminal:

#jstest /dev/input/js0
Driver version is 2.1.0.
Joystick (Twin USB Joystick) has 6 axes (X, Y, Z, Rz, Hat0X, Hat0Y)
and 12 buttons (Trigger, ThumbBtn, ThumbBtn2, TopBtn, TopBtn2, PinkieBtn, BaseBtn, BaseBtn2, BaseBtn3, BaseBtn4, BaseBtn5, BaseBtn6).
Testing ... (interrupt to exit)
Axes:  0:     0  1:     0  2:     0  3:     0  4:     0  5:     0 Buttons:  0:off  1:off  2:off  3:off  4:off  5:off  6:off  7:off  8:off  9:off 10:off 11:off

Now if you push the direction buttons or some other buttons you should see some changes:

#jstest /dev/input/js0
Driver version is 2.1.0.
Joystick (Twin USB Joystick) has 6 axes (X, Y, Z, Rz, Hat0X, Hat0Y)
and 12 buttons (Trigger, ThumbBtn, ThumbBtn2, TopBtn, TopBtn2, PinkieBtn, BaseBtn, BaseBtn2, BaseBtn3, BaseBtn4, BaseBtn5, BaseBtn6).
Testing ... (interrupt to exit)
Axes:  0:<strong>-32767</strong>  1: <strong>32767</strong>  2:     0  3:     0  4:     0  5:     0 Buttons:  0:off  1:<strong>on</strong>   2:<strong>on</strong>  3:off  4:off  5:off  6:off  7:off  8:off  9:off 10:off 11:off

If while pushing the buttons you see some number changing from off to on you’re done, that’s how the different buttons are mapped in Linux.

Note: At first this was not working for me, I switched the connection of the Joypad in the adapter and everything started to works, so apparently there is in the adapter a port 1 and a port 2 and you have to use port 1.

How to map the joypad buttons on keys

The most simple thing to do to use the joypad is to map every button with a keyboard key, in this way you’ll be able to use it with all games that don’t have a native support for joypad, a good software that can do this is QjoyPad.
QJoyPad takes input from a gamepad or joystick and translates it into key strokes or mouse actions, letting you control any XWindows program with your game controller.

Its main features are

• Move and click the mouse with your joystick
• Auto-detects how many joysticks you have and how many buttons and axes each supports
• Support for devices with more than two axes
• Save as many layouts as you want and switch between them quickly
• Swap layouts on the fly from the command line or from a script
• Set or reset all the keys at once in a flash
• Adjust the sensitivity of every axis independently
• Quietly hides in your system tray, running in the background without taking up space
• For window managers without a system tray, QJoyPad can run without the tray icon.
• Make an axis “Gradient” so that a light push does a little and a harder push does more – now with customizable curves!
• Make a button “Sticky” if you don’t feel like holding it down all the time
• Turn on Rapid Fire so you don’t wear out your gamepad!
• Native tray icon code making putting it in your start up entry simple
• To install it on Debian, Ubuntu and Mint open a terminal and run the command

sudo apt-get install qjoypad

Now you should find the qjoypad icon on the game menu, or you can start it from a terminal with the command qjoypad, in both way you should see a new joypad icon on your system tray.

If you left click on it the main window of qjoypad will open:

From this window you can configure the keys for axis1 (Horizontal) and axis2 (vertical) and all the buttons, and save them in a layout.
Once done save and … start your favorite game.

Conclusions

To be honest I was very skeptical about this solution, but in really few time I’ve been able to configure the joypad and use it with Shank 2 a game unplayable with just the keyboard (at least for me).
To me this demonstrate once more that the Gnu/Linux system is mature and setting up peripherals is now not harder than some years ago.

Related posts:

1. How to use a D-LINK – Wireless N 150 usb adapter on Linux
2. Cryptkeeper an applet to manage your EncFS

I’ve changed the GNU/Linux distribution of my home computer from Xubuntu to Mint (XFCE edition) 2 releases ago, and from that date I’ve never regret it, so while I wait for the release of the XFCE edition of Olivia (the code name of Mint 15), I’m glad to publish an interesting article of Manuel and it’s experiences with the Cinnamon edition of Mint 15.
—

The new version of Linux Mint has just been released. The developers have arrived at version 15, the nick name of this version is Olivia. A lot of the changes are specified in the release notes. Among the most striking a new managment for the proprietary drivers and the repository. The writer already used successfully Mint, but in the variant with the XFCE desktop environment. This time, it was decided to give credit to the developers of Mint and use the official version with Cinnamon instead of XFCE.

No more pleasantries. The new Mint soon proved to be a bomb, with really gew things to complain about. Installed as usual directly from an USB stick, in around twenty minutes we had everything set and ready. All the hardware of our laptop Dell Inspiron 1525 has been recognized on the fly, but we had to turn on the of the proprietary wireless driver in order to use the wireless connection. A few automatic updates remained to be done, and so, we started with our tests.



For simple matter of habit, coming from XFCE, we moved the main panel at the top. Linux Mint is installed with a lot software ready for use. We limited ourselves to add some tools which we use daily: IBus to handle input in Chinese, Double Commander, the text editor Geany, SMPlayer, Clementine for music, Dropbox, Skype and little else.

A small note for those who use Double Commander like us. The GTK version has a bug with the animation effects of the windows. If you try to delete a file, the popup of cancellation remains on the screen and it is impossible to get rid of it even after a restart of Cinnamon. To resolve this issue and get back to safely use Double Commander, simply avoid using the Fade effect in the settings of the effects of Cinnamon. We hope that soon this bug will be fixed.

For those who do not know Double Commander or prefer to use what Linux Mint provides, the file manager Nemo, derived from Nautilus that is the default in Ubuntu, offers everything you need.

A fresh installation of Linux Mint also miss the Windows fonts, but just type the following command in the terminal to resolve this:

sudo apt-get install ttf-installer-mscorefonts

Thanks to Cinnamon, the menu is a little gem of elegance, order and comfort. It is a moment to find all the applications, add them to the panel, reorder, create desktop shortcuts. For those who like hack everything, within the options menu there is the possibility to enter the path of a directory directly in the search box.

There are several settings which you can customize in Linux Mint. Of course you do not have the freedom that you had with XFCE, but we are not so far away. To change the appearance of the system there are two themes available, you can add more themes directly from the system settings without getting lost among websites. However, the first attempt to look for new themes on the web proved to be quite long in spite of our network that was working perfectly. There are also desklets useful to beautify your desktop, and various extensions are easily accessible in the clean and polish panel with the system settings.

A few clicks and tricks and voila, here is how our Olivia in all its glory will look.

Another minor inconvenience experienced was the inability to see other PCs in our local network via the Samba service. To solve the problem is enough to follow this simple procedure:

• from the terminal, run sudo gedit /etc/samba/smb.conf
• under the heading workgroup = WORKGROUP, add: name resolve order = bcast host lmhosts wins
• save and close the file
• open a terminal and type run sudo service smbd restart
• open a terminal and type run sudo service nmbd restart

Wait a few minutes and all is done, our local network was accessible again.

Conclusions

Olivia is proving to be all that Linux Mint has tried to be since it was born. A stable operating system, elegant and easy to use. Rejecting the desktop environments of the latest Ubuntu and Fedora that have so divided the Gnu/Linux community, Linux Mint makes simplicity and comfort its true strength. If you want to find a downside, with Cinnamon the load times at startup are a bit slower than when we were using XFCE, but nothing to tear his hair. GNU/Linux has never been so beautiful.

Related posts:

1. Cinnamon: A New Delicious Flavour For Linux Users To Enjoy
2. New computer, new distro or goodbye Ubuntu, welcome Mint

If pdf is electronic paper, then pdftk is an electronic stapler-remover, hole-punch, binder, secret-decoder-ring, and x-ray-glasses.
pdftk is a simple tool for doing everyday things with pdf documents. keep one in the top drawer of your desktop and use it to:

• merge pdf documents
• split pdf pages into a new document
• decrypt input as necessary (password required)
• encrypt output as desired
• fill pdf forms with fdf data and/or flatten forms
• apply a background watermark
• report pdf on metrics, including metadata and bookmarks
• update pdf metadata
• attach files to pdf pages or the pdf document
• unpack pdf attachments
• burst a pdf document into single pages
• uncompress and re-compress page streams
• repair corrupted pdf (where possible)

Installation

The pdftk package should be available in the repository of the most common distributions so to install it you can usually use your package manager such as:

Debian, Ubuntu, Mint:

apt-get install pdftk

Fedora

yum install pdftk

Arch Linux

yaourt -Sy pdftk

Basic Usage

The basic syntax of PDFTK is the following:

pdftk input_file operations output_file

The operations corresponds to the desired action that you want to do on the files.

• cat Concatenation
• burst Splits a single input PDF document into individual pages.
• dump_data Extraction of metadata, bookmarks (bookmarks) and page labels from a PDF
• uncompress Decompression
• attach_files Inclusion of attachments in a PDF document
• unpack_files Extraction of attachments from a PDF document
• fill_form Fill in PDF forms with FDF1) or XFDF2) data
• background Applies a PDF watermark to the background of a single input PDF
• stamp This behaves just like the background operation except it overlays the stamp PDF page on top of the input PDF document’s pages
• generate_fdf Reads a single input PDF file and generates an FDF file suitable for fill_form
• dump_data_fields Reads a single input PDF file and reports its metadata, bookmarks and page metrics.
• update_info Update metadata

PDFtk Examples

Joining files

Suppose that we want to merge two documents (1.pdf and 2.pdf) in a single file (both.pdf), the command will be:

$ pdftk 1.pdf 2.pdf cat output both.pdf

The cat command assembles pages from input PDFs to create a new PDF. Use cat to merge PDF pages or to split PDF pages from documents. You can also use it to rotate PDF pages. Page order in the new PDF is specified by the order of the given page ranges, this can be useful to:

Merge specific pages from different files

Suppose that we want to merge two documents (1.pdf and 2.pdf) in this way: the first 2 pages of 1.pdf and the even pages from 10 to 20 of 2.pdf, the command will be:

pdftk A=1.pdf B=2.pdf cat A1-2 B10-20even output out.pdf

Splitting files

It’s also possible to split PDF files with pdftk. The burst option breaks a PDF into multiple files — one file for each page:

pdftk mylong_guide.pdf burst

This command will create a lot of files with names corresponding to their page numbers, such as pg_0001 to pg_0125.

Security

Encrypt a PDF document with a 128-bit key and remove all rights (default):

pdftk mydoc.pdf output mycrypted_doc.128.pdf owner_pw foo

Same as above, except password baz must also be used to open output PDF

pdftk 1.pdf output mycrypted_doc.128.pdf owner_pw foo user_pw baz

Decrypt a PDF :

pdftk mycrypted_doc.128.pdf input_pw  foo output déchiffré.pdf

Adding attachments

This feature can be useful to include a document in another format, images, or additional information with a published PDF
Pdftk can attach binary and text files to a PDF with ease. You can even specify what page of the PDF you want the attachment to appear on with a command like this:

pdftk html_tidy.pdf attach_files command_ref.html to_page 24 output html_tidy_book.pdf

This will attach to page 24 of the document html_tidy_book.pdf the html: command_ref.html

Conclusions

probably you don’t need these functionality every day, but if you have to manipulate pdf files in Linux, pdftk it’s your tool.
With it you’ll be able to do a lot of different things with ease, getting good results in no time.

References

Manipulating PDFs with the PDF Toolkit

PDFtk Examples

Related posts:

1. PDF Reader for Linux
2. Show your pdf with style on Linux

lsblk lists information about all or the specified block devices. The lsblk command reads the sysfs filesystem to gather information.
The command prints all block devices (except RAM disks) in a tree-like format by default.



This command can be very useful to check how the different partitions and/or disks are mounted in the system, this is an example on my desktop:

#lsblk 
NAME    MAJ:MIN RM   SIZE RO TYPE   MOUNTPOINT
sda       8:0    0 465.8G  0 disk   
├─sda1    8:1    0  46.6G  0 part   /
├─sda2    8:2    0     1K  0 part   
├─sda5    8:5    0   3.7G  0 part   [SWAP]
└─sda6    8:6    0 415.5G  0 part   
sdb       8:16   0 465.8G  0 disk   
└─sdb1    8:17   0 465.8G  0 part   
  └─md0   9:0    0 465.7G  0 raid10 /data
sdc       8:32   0 465.8G  0 disk   
└─sdc1    8:33   0 465.8G  0 part   
  └─md0   9:0    0 465.7G  0 raid10 /data
sdd       8:48   1  14.9G  0 disk   
└─sdd1    8:49   1  14.9G  0 part   /media/linuxaria/KINGSTON
sr0      11:0    1  1024M  0 rom

From this output you can see that on this desktop I’ve the following disks:

SDA the fist “scsi” disk, in my case a SATA disk.
On this disk the first partition is used for the / filesystem, the second partition it’s an extended partition, the third it’s my swap partition and the last one (sda6) is used for my /home, it’s a BTRFS filesystem and the command don’t recognize it,

SDB and SDC are the two disks that I use in RAID 10 and the filesystem is mounted as /data

SDD it’s an USB stick of 16GB mounted under the directory /media/linuxaria/KINGSTON

An output of a computer with LVM could be:

$ lsblk
NAME                       MAJ:MIN RM   SIZE RO MOUNTPOINT
sda                          8:0    0 298.1G  0
├─sda1                       8:1    0   500M  0 /boot
└─sda2                       8:2    0 297.6G  0
  ├─vg_main-lv_swap (dm-0) 253:0    0   5.8G  0 [SWAP]
  ├─vg_main-lv_root (dm-1) 253:1    0    50G  0 /
  └─vg_main-lv_home (dm-2) 253:2    0 241.8G  0
    └─home (dm-3)          253:3    0 241.8G  0 /home
sr0                         11:0    1  1024M  0

So as you can see this command it’s really easy to use and the output it’s really polish in its tree style, with a glance you can recognize partitions, logical volume and other useful information of your disks.
Running fdisk -l gives similar data. But, fdisk requires root privileges, and It does not understand dm or lvm partitions.

Related posts:

1. Free reserved space in ext3/ext4 Filesystems
2. The Best Filesystem for an external hard disk of 1TB with cross platform support.

Problem: On a long run (a run of 50K+ jobs) it happens “frequently” that 2 jobs finish at the same time and so both take the same ID causing problems to the whole process, we tried to use a simple lock file “touched” just after the job was opening the file with the list of ID, but it seems that this operation it’s too slow and we had some case of failed concurrency again.

The solution was to use the bash function flock

flock(2) it’s used to apply advisory locks to open files. it can be used to synchronize access to resources across multiple running processes. While flock(2) does solely act on files (actually, on file handles), the file itself need not be the resource to which access is being controlled. Instead, the file can be used as a semaphore to control access to a critical section, in which any resource can be accessed without concurrency concerns.

This sound complicated ?

Perhaps a small example will help, this is my /tmp/hello.sh script:

#!/bin/bash
 
set -e
 
scriptname=$(basename $0)
lock="/var/run/${scriptname}"
 
exec 200>$lock
flock -n 200 || exit 1
 
## The code:
pid=$$
echo $pid 1>&200
sleep 60
echo "Hello world"

Some explanation of the interesting parts of the code:

set -e

When this option is on, if a simple command fails for any of the reasons listed in Consequences of Shell Errors or returns an exit status value >0, and is not part of the compound list following a while, until, or if keyword, and is not a part of an AND or OR list, and is not a pipeline preceded by the ! reserved word, then the shell shall immediately exit.

exec 200>$lock

Normally “exec” in a shell script is used to turn over control of the script to some other program. But it can also be used to open a file and name a file handle for it. Normally, every script has standard input (file handle 0), standard output (file handle 1) and standard error (file handle 2) opened for it. The call “exec 200>$lock” will open the file named in $lock for reading, and assign it file handle 200

flock -n 200||exit 1

Tells flock to exclusively lock the file referenced by file handle 200 or exit with code 1. The state of being locked lasts after the flock call, because the file handle is still valid. That state will last until the file handle is closed, typically when the script exits.

After that i collect in the variable $pid the PID of this process and I write it in the lock file, i sleep 60 seconds (to test what happen if the script is run a second time) and at the end I give my message to the world.

And this is the output (in verbose mode) of this script:

First run:

bash -x /tmp/hello.sh 
+ set -e
++ basename /tmp/hello.sh
+ scriptname=hello.sh
+ lock=/var/run/hello.sh
+ exec
+ flock -n 200
+ pid=4683
+ echo 4683
+ sleep 60
+ echo 'Hello world'
Hello world

Second run (while the first it’s sleeping):

bash -x /tmp/hello.sh 
+ set -e
++ basename /tmp/hello.sh
+ scriptname=hello.sh
+ lock=/var/run/hello.sh
+ exec
+ flock -n 200
+ exit 1

The main options that you can use with the command flock are:

-s, –shared
Obtain a shared lock, sometimes called a read lock.

-x, -e, –exclusive
Obtain an exclusive lock, sometimes called a write lock. This is the default.

-u, –unlock
Drop a lock. This is usually not required, since a lock is automatically dropped when the file is closed. However, it may be required in special cases,
for example if the enclosed command group may have forked a background process which should not be holding the lock.

-n, –nb, –nonblock
Fail (with an exit code of 1) rather than wait if the lock cannot be immediately acquired.

-w, –wait, –timeout seconds
Fail (with an exit code of 1) if the lock cannot be acquired within seconds seconds. Decimal fractional values are allowed.

Conclusions

Flock it’s an easy function that can assure you to run multiple jobs/processes without any problem on resources that must be read or write by a single process at time.

Related posts:

1. How to get exit status from a piped command in Linux shell
2. Linux shell, how to use the exec option in find with examples

What’s is HIB ? in short:

The Humble Indie Bundles or Humble Bundles are a series of game bundles that are sold and distributed online at a price determined by the purchaser. The games are multi-platform, DRM-free, and independently developed, and buyers can set the revenue split between the developers, charities and humble bundle organizers.

Thanks Wikipedia.

You have time for another 9 days before  this offer runs out, but let’s take a quick look at the games that you’ll get this time

Dear Esther

The most interesting title in this bundle it’s (In my opinion) Dear Esther.
Dear Esther isn’t what you might consider your typical video game, but therein lies the beauty of it. Instead, it’s an experimental first-person adventure, strongly driven by a fractured narrative. Let yourself wander the abandoned island and its desolate and dreary beaches, and get lost in the sounds of the surf and wind as you try to piece together who you are, and why you were brought to the island.

Dear Esther is a ghost story, told using first-person gaming technologies. Rather than traditional game-play the focus here is on exploration, uncovering the mystery of the island, of who you are and why you are here. Fragments of story are randomly uncovered when exploring the various locations of the island, making every each journey a unique experience.

Forget the normal rules of play; if nothing seems real here, it’s because it may just be all a delusion. What is the significance of the aerial – What happened on the motorway – is the island real or imagined – who is Esther and why has she chosen to summon you here? The answers are out there, on the lost beach and the tunnels under the island. Or then again, they may just not be, after all…

The Dear Esther Linux build on your download page was made by CodeWeavers, which means that it is based on a custom-tailored version of Wine (a re-implementation of the Windows API under Linux). While it is not a “genuine native port”, it should run great on Linux machines and is professionally supported.
The native port is planned to come soon to Humble Indie Bundle 8 customers (though there isn’t an ETA yet).

Little Inferno

Congratulations on your new Little Inferno Entertainment Fireplace! Throw your toys into your fire, and play with them as they burn. Stay warm in there. It’s getting cold outside! Burn flaming logs, screaming robots, credit cards, batteries, exploding fish, unstable nuclear devices, and tiny galaxies. An adventure that takes place almost entirely in front of a fireplace – about looking up up up out of the chimney, and the cold world just on the other side of the wall.

Awesomenauts

Awesomenauts is a 2D multiplayer online battle arena, or MOBA, video game by Ronimo Games with colorful characters and funny cartoon-style theme. This 3 vs. 3 multiplayer action platformer will have you attacking your opponents and their turrets while also defending your own base from attack across a variety of 2-D maps. Choose from a cast of vibrant characters, each with its own unique set of abilities and theme song, and unlock hundreds of upgrades to customize your character’s abilities to each new battle.

Capsized

In a turn of unfortunate events, you’ve crashed on a strange alien planet. Stranded, you’ll need to use a variety of tools and weapons, including a Jetpack, Energy Shield, and Quasar Array, to find the rest of your crew and make it out alive. Capsized is a 2-D platformer filled with colorful detailed landscapes and blood-thirsty monsters. With a campaign mode of 12 missions and an arcade mode, you’ll find that being marooned on an unfamiliar world might not be such a bad thing after all.

Thomas Was Alone

Thomas Was Alone, a minimalistic puzzle-platformer. Start out as Thomas, a red rectangle, then fall and jump through 100 levels as you discover new friends along the way. You’ll run into John, a tall, lanky, and helpful yellow rectangle, Sarah, a pint-sized curious purple rectangle with a powerful double jump, and more, as you fall in love with the characters in this simple but endearing game of quadrilaterals.

And if you pay more than average you’ll get 2 extra games:

Hotline Miami

Hotline Miami is a high-octane action game overflowing with raw brutality, hard-boiled gunplay and skull crushing close combat. Set in an alternative 1989 Miami, you will assume the role of a mysterious antihero on a murderous rampage against the shady underworld at the behest of voices on your answering machine.

Proteus

Proteus is a game of audio-visual exploration and discovery that has you wandering an exotic, mysterious island.
Every world is randomly generated, so each play is just as refreshing and wondrous as the first. As you explore the island and discover its secrets, Proteus is sure to inspire a childlike wonder and delight.

Related posts:

1. Humble Bundle – part 3
2. Humble Indie Bundle 3 it’s now available !

Over the past few years, a handful of different encrypted messaging systems have cropped up and gained prominence, notably Cryptocat and the OTR specification. Now a newcomer to the scene proposes a different way of thinking about encrypted communication, one that borrows from its more well-known older brother, BitCoin.

A project has been started that intends to recreate BitCoin’s decentralized P2P model for seamless message encryption and transmission.
BitMessage was started by Jonathan Warr en late last year and has now made it up to version 0.2.4. One of the most prominent strengths of the BitMessage system is how it enforces anonymity. Similar to how BitCoin allows one to send money to anonymous recipients without advertising metadata to others, BitMessage communicates via simple addresses generated from public keys, which need not be tied to a specific user’s identity.

Similar to BitCoin’s operation, BitMessages are sent out to all users who are connected to the system. Then, each client attempts to decrypt the message if it is intended for that client. Messages not intended for that client will simply be ignored. This presents major issues with scalability, as has been noted with BitCoin’s system. BitMessage responds to this by proposing a so-called “stream” infrastructure. Once the network gets to be a certain size, it will break itself into separate streams. Clients will only connect to a stream if they have a message to send or receive somewhere in that stream. This follows a decentralized model in which certain machines act as “parents” for streams and will aid in advertising the clients it has in its stream, and facilitating the connection.

More than just a decentralized and anonymous messaging system, BitMessage appears to also have limited social messaging capability. As messages are sent out as broadcasts, it would be easy for individuals to simply “subscribe” to the messages that are sent by users they like, then receive them in a manner similar to Twitter, identi.ca or Tent feeds. If this operation is easily worked in to BitMessage clients, it could provide a push for other projects in the decentralized social networking space to put a stronger focus on privacy and security.

Downloading and Installation on Linux

1. Open a terminal and test that you have python, OpenSSL and git installed by opening a terminal and testing them with the following commands :

   python --version openssl version git --version

2. If one or more of the items are not installed, install them, on .deb systems (Debian/ubuntu based systems) use

3. # sudo apt-get install python python-qt4 openssl git

4. In the terminal, change to the directory you want the Bitmessage folder in (but don’t create the bitmessage folder yet!)
5. Clone the git repository by entering the following command:

   # git clone https://github.com/Bitmessage/PyBitmessage

6. Change to the PyBitmessage source directory by entering the command cd PyBitmessage/src
7. Start PyBitmessage by entering the command python bitmessagemain.py
8. Optionally create a startup script that runs the command python PyBitmessage/src/bitmessagemain.py

And this is how the application looks like:

Conclusions

BitMessage is a secure very secure paranoid email system which when run from the command line connects to many remote peer network clients. Anonymity is all but guaranteed it cannot be traced and the message despite working through the peer network can not be hacked intercepted or altered in any way. BitMessage is heavily secure but does not require pgp as this is built in using hash instead, making it simpler to use once you have an address to send to and from, this forming part of the security protocol used. As no mail server is used there is no requirement or function to login, This mail delivery system can be used in a variety of ways, however it cannot send mail using the SMTP (Simple Mail Transfer Protocol) it is completely different and does not transpose at all, BitMessage at least for now does not handle attachments, not a bad thing overall as attachments can hide trojans, but this does limit the scope of how this system can be used.

References:

Bitmessage white paper

Setting Up And Using Bitmessage – An Encrypted Communications Platform Based On Bitcoin

Bitmessage – Decentralized Email Networking

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But what if you don’t want to share a copy on the cloud of your documents but you need to quickly share a document among your computers ?
Usb stick is usually the best option, but there is also an alternative that use the local network to send data among computers: NitroShare

NitroShare is designed to be hassle-free in every aspect. Just install the application on any machine running Ubuntu or Windows and you’re all set. Each machine should discover all of the other machines on the local network. The application integrates with the operating system, using application indicators on Ubuntu and the system tray on Windows.

NitroShare it’s an open source little program, the main purpose is to act as an intermediary (mini server) to transfer data between two computers connected both to a local area network (LAN).

NitroShare introduces the concept of “share boxes”, which are small widgets that are placed on your desktop. Each share box represents another machine on your local network that you can instantly share files with by dropping them on it. (You can also create a share box that will ask you which machine you want to send the files to.)

The main features of NitroShare are:

• dynamic file compress during transfer to decrease transfer time and bandwidth
• CRC checksum generation to ensure file integrity during transfer
• full compatibility with clients running on other operating systems
• a helpful configuration wizard to guide you through setting up the application on your machines
• The application was developed using the Qt framework and therefore runs on any platform supported by Qt, including Windows, Mac, and Linux.

Installation and setup

The official website offers .rpm and .deb packages for both 32 and 64 bit, these will cover a lot of distributions, or if you use Arch Linux you can find it in the AUR repository, if you use Fedora check this link for some suggestion on the setup.

Ubuntu and Mint users can also add a PPA, if they prefer, with the following commands:

sudo add-apt-repository ppa: george-edison55/nitroshare 
sudo apt-get update 
sudo apt-get install nitroshare

After installation, when you first start the program, a wizard will lead you step by step through the setup of the main settings and to automatically connect the computers between which you want to perform data exchange.

Basic Usage

Once installed NitroShare creates a widget on the desktop that provides generic access to the other machines that have the application up and running.
You can also create an indipendent “share box”, for each computer. When you want to send files you just have to drag the file and drop it on the widget of the computer where you want to send the file.

In Ubuntu , the widget also has integration in the system tray and a context menu that opens when you click with the right mouse button on a file or directory within Nautilus.

Conclusions

NitroShare does its job flawlessly. It moves files in a local network easily, simplifying the task a lot, in the past It had problems sending large files , but the bug should be now been fixed, and in general you should use this software to move “small” fils, so < 1 GB.

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2. Install Dropbox On Ubuntu Server (10 & 11)