Category Archives: linux

OSx – VMware – Mandriva resizing partition

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Problem
When you use WMware to run Mandriva or any other distribution on Mac OSx, if you resize the hard disk partition in VMware your Mandriva system won’t automatically resize the partition to use the newly available space.

Solution
To be able to use the available space the quickest solution is:

  • restart your VMware session but run in safe mode
  • start up drakdisk
  • select the partition you want to resize. WARNING (Make sure you back up important data – even though in my case everything went smoothly)
  • umount the select partition and resize using all the avaliable free space
  • after a few minutes you should be able to restart your VMware and login to your virtual machine as normal, and the partition should be resized

problem using capistrano on deployment server after server ip address change

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Problem
After changing the IP address of your staging server the cap deploy does not work any more and gives you the following error:

** [192.168.0.50 :: err] Host key verification failed.
** [192.168.0.50 :: err] fatal: The remote end hung up unexpectedly

Solution
You would need to login to your staging server (as your deployment user) and do an initial checkout for one time for the ssh keys to work.
So you could do something like the following:

$ ssh user_name@staging_server
$sh -c 'git clone -q git_user@192.168.0.50:repo_name /some/tmp/dir/temp_repo_name

Make sure that you reply ‘y’ to the question about the authenticity of the host as in:
The authenticity of host '192.168.0.50 (192.168.0.50)' can't be established.
RSA key fingerprint is xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xxb.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.0.50' (RSA) to the list of known hosts.

Next delete the newly created git project from your tmp directory, and then you should be able to use cap deploy as normal again from your development pc

You tried to assign a String or a Pathname to an uploader, for security reasons, this is not allowed.

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Problem
You would like to use Carrierwave for file uploads, but you get the following error if you are trying to use factories for running your cucumber scripts:

You tried to assign a String or a Pathname to an uploader, for security reasons, this is not allowed.

That happens if you try to assign inside your factory template, to your file field the path like f.file “path_to_file”

Solution

You would need to slightly modify your factory template to use the file path as follows:

f.file File.open(File.join(Rails.root,"path_to_file"))

ImageMagick, RMagick, Debian installation

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Problem
You want to use the rmagick gem in your ruby on rails project, but you need to install the imagemagick first.

Solution
If Imagemagick is not already installed, use the following to install it:
$ sudo apt-get install imagemagick$ sudo apt get install libmagick-dev libmagickwand-dev

You should then be able to install and use the rmagick gem

no such file to load — readline (LoadError) in Rails 3.0.7 – Mandriva 2011 64

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Problem

When you try to run the console rails c in a new Rails 3.0.7 application, in Mandriva 2011 64bit, and when you use rvm, you get the following error:

no such file to load -- readline (LoadError)

Solution

Similar to an earlier post here, the solution is as follows with the new requirements described

It’s quite like likely that the readline libraries are missing from your installation. To find out which ones go to the directory that the error is indicating (ie):

cd ~/.rvm/src/ruby-1.9..2-head

and then to the following:

cd ext/readline

then run the following:

ruby extconf.rb

If you get something like:
checking for readline/readline.h... no
checking for editline/readline.h... no

then you are probably missing the neccessary header files for readline.
so install them in your system (ie in Mandriva):

sudo urpmi lib64readline-dev,

When the package is installed successfully run the following again:

ruby extconf.rb
make
sudo make install

You should now be able to go back to your project and run rails c with no errors.

no such file to load — readline (LoadError) – Rails 3.0.3 console – rvm

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Problem

When you try to run the console rails c in a new Rails 3.0.3 application, and when you use rvm, you get the following error:

no such file to load -- readline (LoadError)

Solution

It’s quite like likely that the readline libraries are missing from your installation. To find out which ones go to the directory that the error is indicating (ie):

cd ~/.rvm/rubies/ruby-1.8.7-p299

and then to the following:

cd ext/readline

then run the following:

ruby extconf.rb

If you get something like:
checking for readline/readline.h... no
checking for editline/readline.h... no

then you are probably missing the neccessary header files for readline.
so install them in your system (ie in Mandriva):

sudo urpmi readline-dev,

In Debian you will need to install libreadline5-dev and maybe libncurses5-dev (apt-get install).

When the package is installed successfully run the following again:

ruby extconf.rb
make
sudo make install

You should now be able to go back to your project and run rails c with no errors.

Splitting big files (Rails log files) in Linux command line

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Problem
You want to examine some big log files (ie Rails production files), on the command line in Linux but they are quite big.

Solution
You can use cat and grep to look for a specific part in the log files. You can also use grep with the A and B parameters to specify how many lines you want to include before and after the search text, but maybe you want to have chunks of the logs to examine. In that case you can use split to split them up in smaller files:

split --bytes=10M input_log_file.log [output_files_or_directory]

In that case you will be splitting your log file on size (–bytes variable), so you can decide depending on the total size of the log file how many files you want. The output files or directory is optional and if you leave it empty it will create the files in your current directory.

You can also split by the number of lines you want in each file like:

split --lines=15000 input_log_file.log [output_files_or_directory]