Installing eAccelerator In Ubuntu Server

December 26, 2010 3 comments

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

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CentOS Firewall Init Script

August 8, 2010 2 comments

I wrote a simple chkconfig compatible firewall init script for CentOS/RedHat/Fedora based Linux systems.

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.

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Print next few lines after pattern in AWK

May 6, 2010 Leave a comment

Input data.txt is a collection report for XYZ corp group by different collection zones.

$ 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
Categories: Linux / Unix, Tutorial Tags: , , ,

Multiple FS in AWK

May 6, 2010 Leave a comment

Sample file:

$ 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
Categories: Linux / Unix, Tutorial Tags: , ,

How to change the hostname in Ubuntu

February 26, 2009 35 comments

To change hostname in Ubuntu or any Debian variant Linux, modify the /etc/hostname and /etc/hosts.

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.

Categories: Linux / Unix, Tutorial, Ubuntu Tags:

Linux is sexy, too

February 24, 2009 3 comments

sexy-linux

Categories: General, Linux / Unix Tags: ,

Ubuntu auto shutdown due to high CPU temperature

February 23, 2009 36 comments

Ubuntu

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.

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