1. Stop MySQL

    sudo /etc/init.d/mysql stop

2. Start the mysqld demon process using the –skip-grant-tables option with this command

    sudo /usr/sbin/mysqld --skip-grant-tables --skip-networking &

3. Login to MySQL as root.

    mysql -u root mysql

4. You done, flush privileges

    FLUSH PRIVILEGES;

5. You might want to change root password.

    UPDATE user SET Password=PASSWORD('YOURNEWPASSWORD') WHERE User='root';
    FLUSH PRIVILEGES;

Install it:

$apt-get install screen

Type:

$screen

It takes you to virtual screen. Do some work, or fire some command. Then type Ctrl+a, d. (this will detach from virtual screen). Close your terminal and go for coffee.

Come back, login to box using terminal (any ssh). Type screen -R to connect to virtual screen.

Unable to start eAccelerator module in Unknown on line 0.

This is because when you upgrade PHP, eAccelerator need to recompile. eAccelerator always seek current version of PHP, so recompile it to get Apache running.

Full log:

SIGHUP received.  Attempting to restart
PHP Warning:  [eAccelerator] This build of "eAccelerator" was compiled for PHP version 5.2.6-1+lenny3. Rebuild it for your PHP version (5.2.6-1+lenny9) or download precompiled binaries.\n in Unknown on line 0
PHP Fatal error:  Unable to start eAccelerator module in Unknown on line 0
PHP Warning:  [eAccelerator] This build of "eAccelerator" was compiled for PHP version 5.2.6-1+lenny3. Rebuild it for your PHP version (5.2.6-1+lenny9) or download precompiled binaries.\n in Unknown on line 0
PHP Fatal error:  Unable to start eAccelerator module in Unknown on line 0
PHP Warning:  [eAccelerator] This build of "eAccelerator" was compiled for PHP version 5.2.6-1+lenny3. Rebuild it for your PHP version (5.2.6-1+lenny9) or download precompiled binaries.\n in Unknown on line 0
PHP Fatal error:  Unable to start eAccelerator module in Unknown on line 0

Useful link:

1. http://groups.google.com/group/eaccelerator/browse_thread/thread/809899bade9f2238

Useful Tips:

If you want apache running quick, simply move eacceletor.ini from /etc/php5/conf.d. If you don’t have that file, you may want to edit php.ini.

1. Option 1: Try Adding it.
   1. Right click on Pannel
   2. Select Add to Panel
   3. Select Network Manager
2. Option 2: Start nm-applet
   1. Go to terminal
   2. Type, $sudo killall nm-applet && nm-applet –sc-disable
3. Option 3: Keep it in start up
   1. System -> Preference -> Startup Applications
   2. Make sure Network Manager exists there with command nm-applet –sc-disable
4. Option 4: Reset Gnom Panel
   1. $gconftool –recursive-unset /apps/panel && killall gnome-panel
5. Option 5: Sometimes if you configure interface manually, Network Manager will disappear, make it auto
   1. $vi /etc/network/interfaces
   2. Comment all lines
   3. Press Esc, Type :wq, then press enter (to save and exit)

$ mkdir ~/.ssh
$ ssh-keygen -q -f ~/.ssh/id_rsa -t rsa

$ chmod go-w ~/
$ chmod 700 ~/.ssh
$ chmod go-rwx ~/.ssh/*

3) Key distribution (upload public key to server)

$ scp .ssh/id_rsa.pub user@yourserver.com:~/

$ cat id_rsa.pub >> .ssh/authorized_keys

(Note: you can avoide 3a-3c by one command

$ ssh-copy-id -i ~/.ssh/id_rsa.pub username@mystery)

ssh -o PreferredAuthentications=publickey user@yourserver.com

sudo aptitude install build-essential

What does it do? It actually install all c/c++ compiler which are necessary to compile source. You can give try.

Suppose you have create helloword.c file. Just do this

cc -c helloworld.c
cc -o helloword helloworld.c
./helloworld

Instead, if you have helloworld.cpp (C++ code)

g++ helloworld.cpp -o helloworld
./helloworld

Happy programming!!