eAccelerator is a free open-source PHP accelerator & optimizer. It increases the performance of PHP scripts by caching them in their compiled state, so that the overhead of compiling is almost completely eliminated. It also optimizes scripts to speed up their execution.

“eAccelerator typically reduces server load and increases the speed of your PHP code by 1-10 times.” – eAccelerator

Step-By-Step Command Line Installation

Download the latest version from eAccelerator website.

Change directory to home/user directory

Make sure you are in your own user directory, to do this use something like the following:

cd /usr/home/username

Download and extract file

Download and extract version 0.9.5.6.1….

wget http://bart.eaccelerator.net/source/0.9.5.3/eaccelerator-0.9.5.3.tar.bz2
tar xvf eaccelerator-0.9.5.3.tar.bz2
cd eaccelerator-0.9.5.3/

Build and install

To use the following phpize and php-config commands you will need to have the PHP development package installed, in Ubuntu you can install the PHP5 development package using:

sudo apt-get install make php5-dev

After checking that this is installed you can continue:

sudo phpize
./configure –enable-eaccelerator=shared
sudo make clean
sudo make
sudo make test
sudo make install

Check install location

Check the install area by changing directories:

cd /usr/lib/php5/

In this directory you should see a folder named like a date string – eg… “20060613”. Remember the folder name, you may need to use this to point to the eaccelerator.so file in the configuration options below.

Add configuration options for eAccelerator to php.ini

Change to the PHP config directory and open the php.ini file for editing:

cd /etc/php5/apache2
sudo vi php.ini

Add the following to end of php.ini file changing folder names appropriately, do not worry if the cache_dir directory does not exist on your system we will create it next:

; eAccelerator configuration
; Note that eAccelerator may also be installed as a PHP extension or as a zend_extension
; If you are using a thread safe build of PHP you must use
; zend_extension_ts instead of zend_extension
;extension = “/usr/lib/php5/20060613+lfs/eaccelerator.so”
zend_extension = “/usr/lib/php5/20060613/eaccelerator.so”
eaccelerator.shm_size = “16”
eaccelerator.cache_dir = “/var/cache/eaccelerator”
eaccelerator.enable = “1”
eaccelerator.optimizer = “1”
eaccelerator.check_mtime = “1”
eaccelerator.debug = “0”
eaccelerator.filter = “”
eaccelerator.shm_max = “0”
eaccelerator.shm_ttl = “0”
eaccelerator.shm_prune_period = “0”
eaccelerator.shm_only = “0”
eaccelerator.compress = “1”
eaccelerator.compress_level = “9”
eaccelerator.allowed_admin_path = “/var/www/eaccelerator”

Create cache directory

The next very important step is creating the cache directory that you configured in the previous step. The default value is /tmp/eaccelerator. It’s easy because it’s writeable to everyone,

Next we will create the cache directory used configured in the previous step:

sudo mkdir /var/cache/eaccelerator

This directory must be writeable by the user eAccelerator runs under (usually www-data):

sudo chmod 0777 /var/cache/eaccelerator

For additional security we could change the owner of the directory to the same user eAccelerator runs under and set 0644 permissions:

sudo chown www-data:www-data /var/cache/eaccelerator
sudo chmod 0644 /var/cache/eaccelerator

Restart Apache

Restart Apache:

sudo /etc/init.d/apache2 restart

[Source: eAccelerator – Installing from source]

It will setup iptables firewall rules allowing anyone to access user defined ports (22,80 by default). It also has the ability to whitelist and blacklist IP’s. I’ve tested it with chkconfig on CentOS 5.

To use it:

1. Create a file named /etc/init.d/firewall
2. Copy and paste the script into it and save
3. Edit the ALLOWED variable with port numbers you want to allow, default is ports 22 (SSH) and 80 (HTTP)
4. Execute:

touch /usr/local/etc/whitelist.txt && touch /usr/local/etc/blacklist.txt

5. Edit the whitelist/blacklist files if you want
6. Execute:

chmod 755 /etc/init.d/firewall

7. Execute:

chkconfig --add firewall && chkconfig firewall on

The script:

#!/bin/bash
# chkconfig: 345 30 99
# description: Starts and stops iptables based firewall
## List Locations
#
WHITELIST=/usr/local/etc/whitelist.txt
BLACKLIST=/usr/local/etc/blacklist.txt
#
## Specify ports you wish to use.
#
ALLOWED="22 80"
#
## Specify where IP Tables is located
#
IPTABLES=/sbin/iptables
##
#DO NOT EDIT BELOW THIS LINE
###
RETVAL=0
# To start the firewall
start() {
  echo "Setting up firewall rules..."
  echo 'Allowing Localhost'
  #Allow localhost.
  $IPTABLES -A INPUT -t filter -s 127.0.0.1 -j ACCEPT
  #
  ## Whitelist
  #
  for x in `grep -v ^# $WHITELIST | awk '{print $1}'`; do
    echo "Permitting $x..."
    $IPTABLES -A INPUT -t filter -s $x -j ACCEPT
  done
  #
  ## Blacklist
  #
  for x in `grep -v ^# $BLACKLIST | awk '{print $1}'`; do
    echo "Denying $x..."
    $IPTABLES -A INPUT -t filter -s $x -j DROP
  done
  #
  ## Permitted Ports
  #
  for port in $ALLOWED; do
    echo "Accepting port TCP $port..."
    $IPTABLES -A INPUT -t filter -p tcp --dport $port -j ACCEPT
  done
  for port in $ALLOWED; do
    echo "Accepting port UDP $port..."
    $IPTABLES -A INPUT -t filter -p udp --dport $port -j ACCEPT
  done
  $IPTABLES -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  $IPTABLES -A INPUT -p udp -j DROP
  $IPTABLES -A INPUT -p tcp --syn -j DROP
  RETVAL=0
}
# To stop the firewall
stop() {
  echo "Removing all iptables rules..."
  /sbin/iptables -F
  /sbin/iptables -X
  /sbin/iptables -Z
  RETVAL=0
}
case $1 in
  start)
  stop
  start
  ;;
stop)
  stop
  ;;
restart)
  stop
  start
  ;;
status)
  /sbin/iptables -L
  /sbin/iptables -t nat -L
  RETVAL=0
  ;;
*)
  echo "Usage: firewall {start|stop|restart|status}"
  RETVAL=1
esac
exit $RETVAL

$ cat data.txt
Total Collection = $10291 {Fri May  8}
zone7   4500
zone8   3545
zone1   1200
zone0   900
zone3   70
zone5   67
zone11  9
Total Collection = $11847 {Sat May  9}
zone1   2800
zone3   2800
zone6   2567
zone8   2300
zone9   1200
zone12  90
zone11  90

Required: We need to find out the top 4 collection zones for each day from the above file. i.e. to print next 4 lines where the pattern “Total Collection =” is found (as the items are sorted on collection amount).

This is how we can achieve this using awk:

$ awk '/^Total Collection =/{c=4;next}c-->0' data.txt
zone7   4500
zone8   3545
zone1   1200
zone0   900
zone1   2800
zone3   2800
zone6   2567
zone8   2300

Now if we need to print the header line also, something like:

$ awk '/^Total Collection =/{c=4;{print}next}c-->0' data.txt
Total Collection = $10291 {Fri May  8}
zone7   4500
zone8   3545
zone1   1200
zone0   900
Total Collection = $11847 {Sat May  9}
zone1   2800
zone3   2800
zone6   2567
zone8   2300

And if you want to just print the date part as the header with top 4 collection zones.

$ awk -F "[{,}]" '/^Total Collection =/{c=4;{print $2}next}c-->0' data.txt
Fri May  8
zone7   4500
zone8   3545
zone1   1200
zone0   900
Sat May  9
zone1   2800
zone3   2800
zone6   2567
zone8   2300

$ cat summary.txt
A|Jan|clerk|02:45
B|Jan|Salesman|02:12
C|Jan|Accountant|03:12
A|Feb|clerk|01:10
B|Feb|Salesman|11:10
B|March|Salesman|3:10
C|Feb|Accountant|3:34

Output Required:

(First field)|(last field converted to minutes)

i.e.
A|165
B|132
C|192
A|70
B|670
B|190
C|214

This is how we can specify two field separators (| and with FS in awk:

$ awk 'BEGIN{FS="[|,:]"; OFS="|"} {print $1,$(NF-1)*60+$NF}' summary.txt

sudo vi /etc/hostname

Change the old hostname to a new hostname.

sudo vi /etc/hosts

Also, change the oldhostname to a new hostname,

192.168.1.100               newhostname

After done, changing the /etc/hostname and /etc/hosts, you need to restart the hostname service.

sudo /etc/init.d/hostname.sh stop

sudo /etc/init.d/hostname.sh start

And then you log out from the shell and log in back. Once logged in, type

hostname

to check on the changes you have made for the hostname.

I use a laptop with Ubuntu 8.10 installed at work. While running the some high process, the CPU temperature get really high and its automatically shutdown the system. This thing happen every 2 or 3 days and its really annoying. The syslog showed the following error message:

ACPI: Critical trip point
Critical temperature reached (100 C), shutting down.

I know it is a safety feature, but really, I can’t afford to keep having the system shutdown while my system doing something important. My system fans are working but for whatever reason my CPU temp exceeds the critical threshold of 99C. On some systems you can see what your threshold is within the BIOS and even edit it but not on this one. So what’s a frustrated developer supposed to do? Well, it turns out you can tell you system to ignore the high temp threshold and to just keep on chugging along. NOTE: This isn’t the best advice I ever gave, if you do this then fry your CPU don’t come bitching to me.

sudo vi /etc/modprobe.d/options

Go to the last line of the file and add:
options thermal nocrt=1

Save the file.

Once you have this option set you need to reconfigure the kernel to pick up these changes, enter the following command:

sudo dpkg-reconfigure linux-image-$(uname -r)

This will update your kernel and then tell you to restart when it is done. Once you restart the system, type the following command the verfiy:

cat /proc/acpi/thermal_zone/*/*

It should display something similar like below.

<setting not supported>
<polling disabled>
state:                   ok
temperature:             52 C
critical (S5):           99 C <disabled>

Now your system won’t restart when the critical heat point is passed. Again, don’t blame me if you hurt your machine by doing this.

1. Reboot the machine.
2. Press the ESC key while GRUB is loading to enter the menu.
3. If there is a ‘recovery mode’ option, select it and press ‘b’ to boot into single user mode.
4. Otherwise, the default boot configuration should be selected. Press ‘e’ to edit it.
5. Highlight the line that begins with ‘kernel’. Press ‘e’ again to edit this line.
6. At the end of the line, add an additional parameter: ‘single’. Hit return to make the change and press ‘b’ to boot.

The system should load into single user mode and you’ll be left at the command line automatically logged in as root. Type ‘passwd’ to change the root password or ‘passwd someuser’ to change the password for your “someuser” admin account.

Reboot

Once your done, give the three finger salute, or enter ‘reboot’ to restart into your machine’s normal configuration.

That’s all there is to it. Now just make sure to write your password down on a post-it and shove it somewhere safe like under your keyboard.

[ Source: Hackzine.com ]

The steps are not too difficult but I did have to find a few places for information. Search on the forum turn up nothing on this subject so hopefully this HOWTO would be helpful to someone out there.

Note: This is not using the OSE version.

Background:
VirtualBox has a very good GUI running on the host to manage guest OS. However when running a server, we typically do not want to run X on it. Fortunately VirtualBox has commandline tools to manage guest systems. It also provides the VirtualBox Remote Desktop Protocol (VRDP) to allow connection to the guest remotely.

Clarification of terms used:
Host – refers to the machine we are trying to install VirtualBox.
Guest – the VirtualBox guest system that is setup on the host.
Remote – the PC that we are working on to connect to the host via SSH.

This setup was done on a fresh install of Ubuntu Server 8.04 with openssh-server installed.

All the following steps are done by SSH into the host from a remote (I’m using Windows for now).

1. Get required packages
Download the Ubuntu package for VirtualBox from http://www.sun.com/software/products/virtualbox/get.jsp

wget "download link here" -O virtualbox_1.6.2-31466_Ubuntu_hardy_i386.deb

We are using the non-OSE version here.

The manual from http://www.virtualbox.org/wiki/Downloads is also very useful.

2. Installation

sudo dpkg -i virtualbox_1.6.2-31466_Ubuntu_hardy_i386.deb

This will generate a bunch of dependencies. Fix them with

sudo apt-get -f upgrade

3. Decide on user, disk files location

First decide which user you want to run VirtualBox. Add this user to the vboxusers group.

sudo usermod -a -G vboxusers vboxuser

By default VirtualBox creates the directory .VirtualBox on the user home directory and put all the config and disk file there. In my setup, I put the disk files in /var/vbox as I had created a large partition for this purpose.

4. Install a guest OS

You will need an iso for the guest OS install CD. Copy or download it to the host. For example we will just use ubuntu-8.04-server-i386.iso

-create a vm

VBoxManage createvm -name ubuntu -register

-config vm

VBoxManage modifyvm ubuntu -memory "256MB" -acpi on -boot1 dvd -nic1 nat

-create a disk

VBoxManage createvdi -filename "/var/vbox/ubuntu.vdi" -size 5000 -register

-add disk to vm

VBoxManage modifyvm ubuntu -hda "/var/vbox/ubuntu.vdi"

-register an install iso

VBoxManage registerimage dvd /var/vbox/ubuntu-8.04-server-i38.iso

-mount iso on vm

VBoxManage modifyvm ubuntu -dvd /var/vbox/ubuntu-8.04-server-i38.iso

-start the vm with port

VBoxHeadless -startvm ubuntu -p 3389 &

If you are running just 1 guest, the -p 3389 is optional. For more than 1 guest, it has to listen to different port.

5. Connect from remote

Since my desktop is still Windows, I use Remote Desktop Connection. (On XP, Start>All Programs>Accessories>Communications)

For Mac, use http://www.microsoft.com/mac/products/remote-desktop/
For Ubuntu, look at http://ubuntuforums.org/showthread.php?t=824710

Just fill in the IP of your host (or IP:port if not the default) and you should see the Ubuntu installation waiting for you.

Other useful commands:

VBoxManage controlvm ubuntu poweroff
VBoxManage controlvm ubuntu reset

Getting Ubuntu Server to run in VirtualBox

After installation and restarting, you may find that the boot up hang with this error

This kernel requires the following features not present on the CPU: 0:6

To fix this, do the following:

1. Reset the guest
2. Hit F12 to choose to boot from the CD. (It goes by pretty quickly, reset again if you miss it.)
3. Select Rescue a broken system
4. After going through the install screens you will get a command prompt. Select to run it on the root system.
5. Install the virtual linux-virtual kernel

apt-get install linux-virtual

6. Reboot and this should fix the restart.

Upgrading kernel
If the kernel on the host is upgraded, the VirtualBox kernel module need to be re-compiled. Do the following steps:

1. apt-get install make gcc linux-headers-2.6.24-19-server (other kernel header, check uname -a)
2. /etc/init.d/vboxdrv setup

It should recompile the VirtualBox module and everything should be working again.

[ Source: kcnnc from Ubuntu Forum ]

Google Chrome

One box for everything
Type in the address bar and get suggestions for both search and web pages.

Thumbnails of your top sites
Access your favorite pages instantly with lightning speed from any new tab.

Shortcuts for your apps
Get desktop shortcuts to launch your favorite web applications.

[ Source: Google Chrome ]