Programming Sharing Tips

Shell Scripting

2009-12-24T10:26:00.000Z

To Use $RANDOM in Linux Ubuntu:

If you're using Edgy, you will have to make the first line of your script:

#!/bin/bash

I do this for all of my scripts, and to make it global as well run this command:

$ sudo dpkg-reconfigure dash

and answer no. Edgy's default shell interpreter is Dash, not Bash. That's why the $RANDOM did nto work before that.

JAVA in Ubuntu

2009-10-27T10:38:00.000Z

Terminal Commands

which java --> where abouts the java installed, e.g. /usr/lib/java
export JAVA_HOME=/usr/bin/java --> Set JAVA_HOME path
echo $JAVA_HOME --> checks where java home directory

Migrating from Trac to Redmine

2009-10-20T14:08:00.001+01:00

Trac

The Trac importer migrates:

Users
Components
Milestones
Tickets
Ticket comments and changes (status and resolution)
Trac specific fields (eg. Resolution) are added as custom fields in Redmine
Ticket files and custom fields
Wiki pages with history

Notes:

User passwords are all set to trac
Ticket ids are preserved if there's no ticket in your Redmine database yet
Custom fields are all created as text custom fields in Redmine

You need the sqlite-ruby gem to access the Trac database.

     gem install sqlite-ruby

Before starting, you need a fresh Redmine database, with default data loaded (required). See Redmine installation by clicking on the left menu.

Step 1:
Run the following command, where test is your Redmine target environment:

      rake redmine:migrate_from_trac RAILS_ENV="test"

Step 2:
The script asks you for your Trac settings:

Trac directory []: /var/trac/myproject
     Trac database adapter (sqlite, sqlite3, mysql, postgresql) [sqlite]:
     Database encoding [UTF-8]:
     Target project identifier []: myproject

Trac directory is the root directory of your Trac environment.

Redmine will look in this directory for db/trac.db (if you choose

sqlite/sqlite3 database) and the attachments directory.
Whenusing a mysql or postgresql Trac database, the script will ask

you for the connection parameters (host, database name, username and

password). Targetproject identifier is the identifier of the Redmine project in which
the data will be loaded (the project is created if not found).

The script gives you the total number of migrated objects.
Now, you should see a project called Myproject in Redmine with your

Trac data loaded in this project.

Where is mysql.socket in Ubuntu & Debian?

2009-10-20T13:43:00.001+01:00

Its in /var/run/mysqld/mysqld.sock

OR

Use mysql_config --socket in the command line to specify where the .sock file is.

FAQ:

While installing Redmine Web tool, you will need to specify mysql.socket before creating the database structure by Editing the database.yml file and entering the follow under the "production"

             production:
                         adapter: mysql
                         socket: /var/run/mysqld/mysql.sock

Redmine

2009-10-20T13:01:00.000+01:00

Redmine is a flexible project management web application. Written using Ruby on Rails framework, it is cross-platform and cross-database.

Installation:

Download and extract the archive or checkout Redmine.
Create an empty database and accompanying user named redmine for example.

For MySQL:

create database redmine character set utf8;
            create user 'redmine'@'localhost' identified by 'my_password';
            grant all privileges on redmine.* to 'redmine'@'localhost';

Copy config/database.yml.example to config/database.yml and edit this file in order to configure your database settings for "production" environment.

Example for a MySQL database:

production:
                      adapter: mysql
                      database: redmine
                      host: localhost
                      username: redmine
                      password: my_password

Generate a session store secret. This is only required on the trunk version of Redmine at r2493 or above. Users installing a released version of 0.8.x can skip this step.
Redmine stores session data in cookies by default, which requires a secret to be generated. This can be done by running:

           rake config/initializers/session_store.rb

Create the database structure, by running the following command under the application root directory:

           rake db:migrate RAILS_ENV="production"

It will create tables and an administrator account.

Insert default configuration data in database, by running the following command:

           rake redmine:load_default_data RAILS_ENV="production"

This step is optional but highly recommended, as you can define your own configuration from scratch. It will load default roles, trackers, statuses, workflows and enumerations.

Setting up permissions

           NB: Windows users have to skip this section.
           The user who runs Redmine must have write permission on
           the following subdirectories: files, log, tmp (create the
           last one if not present).
           Assuming you run Redmine with a redmine user:

mkdir tmp public/plugin_assets
                   sudo chown -R redmine:redmine files log tmp public/plugin_assets
                   sudo chmod -R 755 files log tmp public/plugin_assets

Test the installation by running WEBrick web server:

           ruby script/server webrick -e production

Once WEBrick has started, point your browser to http://localhost:3000/.
You should now see the application welcome page.

Use default administrator account to log in:

login: admin
password: admin

You can go to Admin & Settings to modify application settings.

ENJOY!

Create a FORM in Django

2009-10-16T11:46:00.002+01:00

FORM OBJECTS: put the code below in models.py

from django import forms

class ContactForm(forms.Form):
    subject = forms.CharField(max_length=100)
    message = forms.CharField()
    sender = forms.EmailField()
    cc_myself = forms.BooleanField(required=False)

Using a FORM in a VIEW: put the code below in views.py

def contact(request):
    if request.method == 'POST': # If the form has been submitted...
        form = ContactForm(request.POST) # A form bound to the POST data
        if form.is_valid(): # All validation rules pass
            # Process the data in form.cleaned_data
            # ...

            form.save() # Will save the POST data in the Database
            return HttpResponseRedirect('/thanks/') # Redirect after POST
    else:
        form = ContactForm() # An unbound form

    return render_to_response('contact.html', {
        'form': form,
    })

FORMS FIELD TYPES GO HERE

Displaying a form using template


{{ form.as_p }}

How do you set up master-master replication in MySQL?

2009-10-13T14:37:00.002+01:00

http://crazytoon.com/2008/02/29/mysql-how-do-you-set-up-mastermaster-replication-in-mysql-centos-rhel-fedora/

Fail-Over, Client Side

2009-10-12T11:04:00.000+01:00

http://onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql-replication.html?page=6

Measuring circular replication performance

2009-10-12T11:03:00.002+01:00

http://onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql-replication.html?page=3

Circular replication failure recovery

2009-10-12T10:59:00.002+01:00

http://onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql-replication.html?page=5

Automatic Fail-Over

2009-10-12T10:37:00.004+01:00

Setting Up a Multimaster Replication System

2009-10-09T11:34:00.001+01:00

Good tutorial here
Useful Tips by Patrick Galbraith

How To Set Up Database Replication In MySQL

2009-10-08T15:03:00.002+01:00

In the meantime please follow the link below
http://www.howtoforge.com/mysql_database_replication

Manage mySQL Backup Automatically

2009-10-07T16:00:00.001+01:00

A script to take daily, weekly and monthly backups of your MySQL databases using mysqldump. Features - Backup mutiple databases - Single backup file or to a seperate file for each DB - Compress backup files - Backup remote servers - E-mail logs and More..

Please click here to download the automysqlbackup.sh script

How to Set Up Replication

2009-10-06T16:53:00.001+01:00

follow the link below
http://dev.mysql.com/doc/refman/5.0/en/replication-howto.html

Data Backup

2009-10-06T10:07:00.003+01:00

MySQL Backups using LVM Snapshots

Configure Apache on Mac

2009-10-04T17:52:00.000+01:00

By default, Apache is turned off. To start it, got to your System Preferences, click on Sharing, and then check the Web Sharing checkbox in the list of services.
Start, Stop and Restart Apache from the command line sudo apachectl start or sudo apachectl stop or sudo apachectl restart

RESTful APIs

2009-10-02T10:25:00.001+01:00

Django-Piston:
A mini-framework for Django for creating RESTful APIs. Piston is a relatively small Django application that lets you create application programming interfaces (API) for your sites. For usage follow the steps:

Install it from here
For full documentation click here

Linux Ubuntu 9.04 Useful Commands Tips

2009-10-01T11:32:00.002+01:00

ctrl+h to reveal hidden folders.
In terminal:

Use sudo for root directory
sudo apt-get install PACKAGENAME to install software package
sudo rm -r DIRECTORY to delete folder and its content files
sudo mkdir -p DIRECTORY to create new folder
sudo nano FILENAME.TYPE to create new file with data init

System -> Administration -> Synaptic Package Manager to install software packages manually

Extra stuff will be added on regular basis! Please feel free to comment more stuff, which I will add to this post after verification.

Cloud Computing Amazon Reviews

2009-09-30T11:51:00.001+01:00

Any reviews about the Amazon Elastic Compute Cloud (Amazon EC2), as I want to use it for hosting. Please comment your views. thanks.

Django (Python Framework) Useful Tips

2009-09-30T11:35:00.012+01:00

Using the Command line:

Django Installation look at Installation Guide
Creating Project: python django-admin.py startproject MYSITE
Creating Module(Class): python manage.py startapp CLASSNAME
Update DB: python manage.py syncdb
Run Django Server: python manage.py runserver
View Models in SQL: python manage.py sql MODELNAME
Validate SQL Models: python manage.py validate
Create tables in DB:run No.6 then No.4
Shell Access: python manage.py shell

Django Debug Toolbar:

The Django Debug Toolbar is a configurable set of panels that display various debug information about the current request/response. It is a small toolbar that, when activated, situates itself in the top-right location of the browser window. When particular panels are clicked, more details about that panel's content are displayed. For Installation follow the steps below:

Download the package from here
Install python-profile from the Synaptic Package Manager
Add the debug_toolbar directory to your Django python project directory.
Add the following middleware to your project's settings.py file:

'debug_toolbar.middleware.DebugToolbarMiddleware',

Add debug_toolbar to your INSTALLED_APPS setting so Django can find the template files associated with the Debug Toolbar.
Run Django server
Open your Django project URL e.g. http://localhost:8000/admin if your admin page is activated

Install it from here
For full documentation click here

Django Python Comment Code:

# for one line comment
""" code """ for whole set

Web Services in Python + Django

2009-09-30T09:56:00.020+01:00

Using the Django-Piston: lets you easily create programmatic RESTful APIs for your Django website.Getting Started:

Step 1:
place your API code in a separate folder, e.g. 'api'.
Your application layout could look like this:

urls.py
settings.py
myapp/
   __init__.py
   views.py
   models.py
api/
   __init__.py
   urls.py
   handlers.py

Step 2:
place your API code in a separate folder, e.g. 'api'.
Your application layout could look like this:

urlpatterns = patterns('',
   # all my other url mappings
   (r'^api/', include('mysite.api.urls')),
)

Web Link Checker (Spider Crawler Program)

2009-09-29T23:08:00.004+01:00

I developed my own spider crawler program to spider my website and checks if there are any broken links but it is not very powerful. I did a research and found many available programs out there, which are written in PHP, C, Python and lot more, but the problem is that I am looking for a program that POST Data forms by submit then spider the rest of the website, as I have a Login Page at the start, which is required.

Any help guys!

Multi-Threading

2009-09-29T23:00:00.004+01:00

Useful tip on here.

PHP + MySQL

2009-09-29T22:58:00.002+01:00

1) Connect to Database
    $con = mysql_connect('YourDBHost', 'YourUsername', 'YourPassword');
    if (!$con)
    {
        die('Could not connect: ' . mysql_error());
    }

2) Destroy Database
    $sql = 'DROP DATABASE yourDBName';
    if (mysql_query($sql, $con))
    {
        echo "Database yourDBName was successfully dropped\n";
    } else
    {
        echo 'Error dropping database: ' . mysql_error() . "\n";
    }

3) Create Database
    $sql = 'CREATE DATABASE yourNewDBName';
    if (mysql_query($sql, $con))
    {
        echo "Database yourNewDBName created successfully\n";
    } else
    {
        echo 'Error creating database: ' . mysql_error() . "\n";
    }

4) Executing .sql file that contains more then one query from PHP

    $file = 'your file path';
    if (!file_exists($file)) {
    echo "The file $file does not exist.";
    }
    $str = file_get_contents($file);
    if (!$str) {
    echo "Unable to read the contents of $file.";
    }
    $sql = explode(';', $str);
    mysql_select_db('your database name', $con);
    foreach ($sql as $query)
    {
        if (mysql_query($query, $con))
        {
            echo "Database tables added successfully\n";
        } else
        {
            echo 'Error adding tables to database: ' . mysql_error() . "\n";
        }
    }