If you ever have the need to change a linux user’s login and home directory, here is a quick tip:
To change the users home directory, execute the following:
usermod -l <newname> -d /home/<newname> -m <oldname>
And to change the group of the user, execute the following.
groupmod -n <newgroup> <oldgroup>
Just make sure you are logged in as a different user before executing the same. You can either login as root user or create an other user with sudo privileges to execute the commands.
If you happen to have setup Zend Debugger for debugging your PHP code and you encounter the following error in the webserver error log:
Zend Debugger: Cannot read a valid value of zend_debugger.httpd_uid or zend.httpd_uid, will not perform dropping of privileges
then your setup will fail when you try to debug over a tunnel. This is caused by the debugger not being aware of the uid of the process which runs the web server.
To fix this, we need to find the user ID of the httpd process that runs the Zend Debugger. One way of finding the UID is by opening up the /etc/passwd file. You should see something similar to:
_www:*:70:70:World Wide Web Server:/Library/WebServer:/usr/bin/false
Now to fix the problem, we update the zend config in the php.ini file and restart the webserver. Here is my complete zend debugger configuration:
Now for some real debugging :).
I have come across several people trying to do this in a convoluted way. Here is the simple way of adding PDT to your Flash Builder IDE.
Since current Flash Builder is basically built on Eclipse Galileo, you just have to add the update site for Galileo
In Flash Builder, go to
Help > Install New Software
Click on “Available Software Sites” link, which should open up “Available Software Sites” window. If you don’t have the Galileo update site already configured, add a new Software site. Call it “Eclipse 3.5 updates” and add the URL: http://download.eclipse.org/releases/galileo/
Back in the “Available Software” screen, select “All available sites” for the “Work with” section. In the search input below that, type in PDT and you should see PDT as an item on the search result. Select it and click the next button. Eclipse will now prompt you with a review screen of the packages which are going to be installed. Click next and complete the installation. You may have to restart the IDE for the changed to take affect.
Shown below is the review screen of PDT installation.
Yes, I am back! After a long absence of over 2 years I hope to blog again. Lots of things have happened since the last time I wrote an entry. Life has changed ever since I became a father around 2 years ago. My son Denzel will be 2 years old in September and it has been a hectic but enjoyable journey so far.
I have always had the need to calculate the age as year and month from a MySQL field of type date. No doubt you can achieve this with a bit of PHP, but when you require to do the conversion right from MySQL, you can only go as far as getting the age in “years”.
I have used here a MySQL stored routine to achive this:
DELIMITER $$ DROP FUNCTION IF EXISTS `my_database`.`getage` $$ CREATE DEFINER=`root`@`localhost` FUNCTION `getage`(pdate DATE) RETURNS char(30) DETERMINISTIC BEGIN DECLARE years INT; DECLARE months INT; DECLARE days INT; DECLARE current_year INT; DECLARE current_month INT; DECLARE current_day INT; DECLARE year_diff INT; DECLARE month_diff INT; DECLARE day_diff INT; DECLARE yearstring CHAR(6); DECLARE monthstring CHAR(7); SELECT YEAR(pdate) INTO years; SELECT MONTH(pdate) INTO months; SELECT DAY(pdate) INTO days; SELECT YEAR(CURRENT_DATE()) INTO current_year; SELECT MONTH(CURRENT_DATE()) INTO current_month; SELECT DAY(CURRENT_DATE()) INTO current_day; SELECT (current_year - years) INTO year_diff; SELECT (current_month - months) INTO month_diff; SELECT (current_day - days) INTO day_diff; if (current_month < months) THEN SET month_diff = (((months - 12) * -1) + current_month); SET year_diff = (year_diff - 1); END IF; if ( month_diff = 1 ) THEN SET monthstring = "month"; ELSE SET monthstring = "months"; END IF; if ( year_diff = 1 ) THEN SET yearstring = "year"; ELSE SET yearstring = "years"; END IF; if ( year_diff = 0 ) THEN RETURN CONCAT_WS(' ', month_diff, monthstring); ELSE if (month_diff > 0) THEN RETURN CONCAT_WS(' ',year_diff, yearstring, month_diff, monthstring); ELSE RETURN CONCAT_WS(' ',year_diff, yearstring); END IF; END IF; END $$ DELIMITER ;
You can then make use of the stored routine to convert Dates into ages by doing so:
SELECT getage(BirthDate) as UserAge FROM my_database.users
Arduino is a tool for making computers that can sense and control more of the physical world than your desktop computer. It’s an open-source physical computing platform based on a simple microcontroller board, and a development environment for writing software for the board.
Unfortunately the serial port communication driver (RXTX) which comes with the arduino download is not 64 bit compatible. I will describe here how I successfully compiled & installed the driver to get the Arduino IDE running on a 64 bit openSUSE installation. Most of the instructions should be pretty straight forward to be replicated on an other rpm based distribution. For ubuntu/debain based distributions, you can find the instructions provided by Tero Karvinen useful.
Packages Required for Arduino IDE
The following packages are required to run the Arduino IDE:
Linux USB Serial Converter Driver
Besides the above software, you will also need a compatible kernel. This means version 2.6.x or at least 2.4.30. For example, it needs USB serial support with the FTDI driver. After connecting an Arduino board to your computer via an AB USB cable, it should load the ftdi modules automatically. Ensure ftdi_sio and usbserial modules are loaded by executing:
lsmod | grep ftdi
It should return output similar to whats shown below:
ftdi_sio 54280 0 usbserial 52688 1 ftdi_sio usbcore 156456 6 ftdi_sio,usbserial,usbhid,ohci_hcd,ehci_hcd
If not, as root, run:
If there are no errors from the above command, then the module is loaded successfully.
The Arduino IDE is java based and RXTX  is a native java library providing serial and parallel communication for the Java Development Toolkit. The RXTX lib uses lock files by default. So Before you use lock files you need to do one of two things:
- Be the root or uucp user on your machine whenever you use rxtx
- Or add the specific user that needs to use rxtx to the group uucp. (preferred)
Add your user account to the uucp group by going to yast2 > Security and Users > User Management. Once you have added yourself to the group, you will need to restart your session to make it affective. Once you are in the new session, verify that your account belongs to the uucp group by executing “groups” on the shell. It should give return you a list of groups your account belongs to.
Ever had problems finding a package for your favorite application for your favorite distro? Are you an application developer or project contributor, and want to learn how to provide binary packages for all the popular distros (including openSUSE) automatically?
Using the openSUSE Build Service, you can provide software packages for most popular Linux distros using one single service. Rather than maintaining separate systems to build packages, you can take advantage of the openSUSE Build Service and let it do most of the work.
To learn how to leverage the build service, join the openSUSE community on April 4th and 5th on IRC to hone your package building skills. The Packaging Days II event will be held on Freenode at #opensuse-buildservice. Community members will be standing by to provide support and answer questions about using the build service and creating packages.
I have been using the popular open source multimedia programme called mythtv for a while now. Apart from recording my favourite TV shows, I also utilise the various modules like mythmusic, mythnews, mythvideo and mythweb. Though you can use mythvideo to view videos which are not tv recordings, there are no specific modules which can import a show into mythtv.
But wait, just when you think its not possible to import a show into the mythtv recordings, there is a way to do so. There is a perl script called “myth.rebuilddatabase.pl” which comes with the mythtv-doc package of mythtv. Usually the “myth.rebuilddatabase.pl” script resides at “/usr/share/doc/packages/mythtv-doc/contrib/” folder. Else, If you are on an rpm based system you can look for its path with the following command:
rpm -qal "myth*" | grep "\.pl"
This should return all the available perl scripts which are distributed with mythtv. Now to use the script, we need make a copy of the script to your home folder and configure it. Edit the file and update the relevant mysql mythtv database connection details. Now copy the tv show files which you want to import, into your mythtv recordings folder.