git: fatal error: `chdir’ failed: permission denied.

Trying to use the heroku gem to clone a project and do local modifications I got the following error:

git: fatal error: `chdir' failed: permission denied.

It turns out that in Mandriva, when using:

sudo urpmi git

what gets installed is the ‘GNU Interactive Tools’ that has nothing to do with the git version control system.
So make sure you first uninstall the git installed:

sudo rpm -e git

and then install the Git – Fast version control system, by doing:

sudo urpmi git-core

You should then be able to clone a heroku application:

heroku clone myapp

Ext.ux.grid has no properties error

Trying to use ExtJS with RubyOnRails on Heroku, gives the following error and a blank page in Firebug.

Ext.ux.grid has no properties
Line 141

In Heroku, you will probably have to manually upload the files from the ExtJS library, as well as the ext_scaffold plugin.
When you do that, two files that ext_scaffold needs, and which they should be located in ext_scaffold/assets/javascripts should be copied to public/javascripts.
The files are:


Converting Paradox tables to MySQL sql in Linux

You want to convert some legacy tables created in Paradox (.db, .px) to another format so you can use it in MySQL.

Download the px tools from here.

Follow the instructions, in the INSTALL file after you untar the file.
You should have to do the usual three step linux installation:

sudo make install

Afterwards to make sure that the .db file is a paradox file run:

pxinfo -f  path/to/paradox/db/file.db

The program should read the header and report back with something along the lines:

File-Version: Paradox 7.x
Filetype: indexed .DB

To export each Paradox db file to an sql statement run the following:

pxsqldump -d mysql -f path/to/paradox/file.db > path/to/mysql/exported/file.sql

Installing sqlite3-ruby in Mandriva and Rails 2.0.2

After upgrading to Rails 2.0.2 when trying to install the sqlite3-ruby gem got the following error:

ERROR:  Error installing sqlite3-ruby:
ERROR: Failed to build gem native extension.
/usr/bin/ruby extconf.rb install sqlite3-ruby
checking for sqlite3.h... no
make: *** No rule to make target `ruby.h', needed by `sqlite3_api_wrap.o'.  Stop.
Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.1/ext/sqlite3_api/gem_make.out

In Mandriva you need to install the ruby-sqlite3 and the development libraries first, like:

sudo urpmi ruby-sqlite3
sudo urpmi libsqlite3-devel

After that you should be able to install the gem as normal.

Upgrading to Rails 2.0.2 problems/solutions

Upgrading from Rails version 1.2.3 to version 2.0.2.
Following the suggestion in DH’s weblog here when using sudo gem install rails -y, it gets the trunk version of rails which at the time was
This causes a few problems and breaks a few more things.

In order to get back to the latest stable version, you have to uninstall a few of the gems installed from the trunk version.
If you have installed the latest version of top of an existing one using gems, then doing:

gem list --local

will give you all the installed versions of the gems. Something like:

actionmailer (, 2.0.2, 1.3.3)
actionpack(, 2.0.2, 1.3.3)
rails(, 2.0.2, 1.2.3)

Make sure you uninstall all the gems with version number

sudo gem uninstall rails
sudo gem uninstall actionmailer
sudo gem uninstall actionpack
sudo gem uninstall activerecord
sudo gem uninstall activeresource
sudo gem uninstall activesupport
sudo gem uninstall rails

In each of the above commands the gem package manager should ask you to select the one you want to uninstall.
Pick the one with the (or other version later than 2.0.2).

At the end if you list the gems again you should only have gems going up to version 2.0.2

An extra step I had to take for making the migrations work was to install rake again:

sudo gem install rake

After all these my installation seems to be working fine again.