Unable to run a 32-bit program on 64-bit machine

Qs. I compiled a small "hello world" C program on Ubuntu 10.04 32 bit machine. Then I put the executable(a.out) on Ubuntu 12.10(64 bit) VMWare virtual machine and tried to execute it(./a.out). The OS does not identify the file and says 'No such file or directory'. But when I put the same executable on a Ubuntu 12.10(64 bit) running on a 64 bit laptop, it runs fine and I get the desired output. The VM is running on IBM Blade Servers. I wanted to know why the results for a VM?

Ans:
The message No such file or directory does not refer to your executable file: a.out. Instead it refers to a helper program that's needed to run the 32 bit dynamically linked executable a.out.

Source: http://askubuntu.com/questions/351827/unable-to-run-a-32-bit-program-on-64-bit-vm

PHP is running with user ID=33, but this directory is owned by the system user with ID=0

Error:PHP is running with user ID=33, but this directory is owned by the system user with ID=0

Solution:
 sudo chown -R  www-data:www-data  /var/www/X2Engine/

before changes it was

drwxrwxrwx 3 root root    4096 Mar  4 16:24 X2Engine

--
Pranaw Kumar
C-DAC MUMBAI
Ph-(+91) (22) 26201606

How to enable or activate the apache mod_rewrite module

sudo a2enmod rewrite

then restart apache by

/etc/init.d/apache2 restart

How to change Apache Document root Directory in Ubuntu 13.10

http://www.binarytides.com/install-apache-ubuntu-13-10/

“Adding Printer” dialog asks for root password?

start printer configuration window through command line:

sudo system-config-printer

error while loading shared libraries: libtk8.4.so: cannot open shared object file: No such file or directory

Problem: On some Linux systems, launching oommf.tcl yields an error message of the form

error while loading shared libraries: libtk8.4.so: cannot open shared object file: No such file or directory

Solution: This typically happens because the libtk8.x.so (and libtcl8.x.so) files are installed in a directory not included in the ld.so runtime linker/loader search path. One way to fix this is to add that directory (say /usr/local/lib) to the LD_LIBRARY_PATH environment variable. For example, add

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

to your ~/.bashrc file (bash shell users) or

setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:/usr/local/lib

to your ~/.cshrc file (csh or tcsh shell users). Another option is to modify the ld.so cache; see the ld.so and ldconfig man pages for details.

source: http://math.nist.gov/oommf/software-patchsets/oommf12a3/

Not able to login via GUI : Error in locking Xauthority file

1. Switch to command line "Ctrl" + "Alt" + "F6″

2. enter login, provide user name and password

3. type startx

   it should switch to GUI mode

but if you get Error in locking Xauthority file, try following:

The error i got means i do not have authorize to access $HOME/.Xauthority file in my user directory.

If you have the same problem, simply run chown as root to change the ownership back to the user. At the terminal as root, go to /home/user
# cd /home/user

list all files with ownership
# ls -a -lh

change file/files ownership to your user
# chown user:user .Xau*

reboot the machine, everything should be working as normal now.

Source: http://namhuy.net/1077/fixing-error-in-locking-authority-file-xauthority.html