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

Grub Re-installation

You need to have Ubuntu Live CD or Live USB. Normal session can be used to repair the grub. Boot using your Ubuntu Live CD or Live USB, while booting choose Try Ubuntu.

Once booted then open a terminal, and run the following command one by one to install the boot repair.

To add boot-repair to the repository

sudo add-apt-repository ppa:yannubuntu/boot-repair

To Update your repository

    sudo apt-get update

To install boot-repair

sudo apt-get install -y boot-repair

Once Installation complete run boot-repair on terminal by typing the following command or select it by System->Aministration->Boot Repair.

boot-repair

NOTE: Update the Boot Repair if its newer version is available.

Source: http://www.howopensource.com/2012/05/reinstall-recover-grub-from-ubuntu-12-04-live-cd-usb/

Host key verification failed...

Problem:    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!   

IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
96:f3:6d:5b:73:38:f0:31:3e:3f:11:91:a9:f8:ba:b4.
Please contact your system administrator.
Add correct host key in /home/boss/.ssh/known_hosts to get rid of this message.
Offending key in /home/boss/.ssh/known_hosts:6
RSA host key for 202.141.151.19 has changed and you have requested strict checking.
Host key verification failed.

Solution:

Open ~/.ssh/known_hosts and delete all lines, after just reconnect and you will get a new key.

eg. pico ~/.ssh/known_hosts and delete all lines

how to create xpi file

Do cd pluginDirectory/ first and then zip -r ../plugin.xpi *

-

How do I know what version of Linux is running?

use:
uname -a && cat /etc/*release^C

Add correct host key in ~/.ssh/known_hosts

Error: Add correct host key in /home/boss/.ssh/known_hosts to get rid of this message.
Offending key in /home/boss/.ssh/known_hosts:1
RSA host key for 202.141.151.19 has changed and you have requested strict checking.
Host key verification failed.

Solution:

1. get the rsa key of your server:

   $ ssh-keyscan -t rsa server_ip  # server_ip SSH-2.0-OpenSSH_4.3  server_ip ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAwH5EXZG...  

2. and on the client, add this key to ~/.ssh/known_hosts:

   server_ip ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAqx9m529...(the offensive key)  server_ip ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAwH5EXZG...