The following Sass will do it:

hr
  color: #ddd
  background-color: #ddd
  border: none
  height: 1px

When doing a query like this:
SELECT id FROM users WHERE (users.id IN (899,1084,1095,100,2424,2429,2420))

the order of the returned records is undefined. To force the query to return the records in a given order, you have to add ORDER BY FIELD(id, 899, 1084, ...)

So the query looks like this:
SELECT id FROM users WHERE (users.id IN (899,1084,1095,100,2424,2429,2420)) ORDER BY FIELD(id,899,1084,1095,100,2424,2429,2420);

This method is defined automatically and only given for boolean attributes

create_table "users", :force => true do |t|
  t.boolean  "email_confirmed"
end

# you may now say:
User.email_confirmed?

validates_attachment_content_type :image, :content_type => /^image\/(jpg|jpeg|pjpeg|png|x-png|gif)$/, :message => 'file type is not allowed (only jpeg/png/gif images)'

This will tunnel HTTP requests to one given domain and port through an intermediary SSH server:

ssh -L 8080:targethost:80 tunnelhost

http://localhost:8080 will now connect you to http://targethost:80, tunnelling all data through tunnelhost via SSH.

Note that the connection between tunnelhost and targethost will still be unencrypted in this example.

Open the configuration file:

gksudo gedit /usr/share/vte/termcap/xterm

Find a line like this:

:co#80:it#8:li#24:\

Change the first and last number to your desired columns and rows:

:co#160:it#8:li#40:\

Save your changes and close all open terminals. New terminals should now open with the new size.

Ubuntu lets you mount an SSH shell into Nautilus from Places -> Connect to server (select "SSH" as server type).

In order to copy a file over SSH from a shell:

scp filename username@remotehost:

The trailing ":" directs the file to username's home directory on the remote host.

You can also copy a file from the remote host to your local machine:

scp remotehost:remotepath localpath

Screen is great for long running tasks, where you want to log in every few hours and days and keep your session alive indefinitely.

To create a new screen, do

screen -Rd screenname

This will also reattach an existing screen with that name.

Once you're in the screen, CTRL+A will bring up the menu, d detaches the screen. You can close your shell, screen and all applications running inside of it will remain alive.

Scrolling inside a screen

• Bring up the menu with CTRL+A
• Press Esc
• You can now scr...

In a nutshell: to avoid your shell character set from messing with imports, use -r to export and SOURCE when importing.

Dumping safely

# Do not do this, since it might screw up encoding
mysqldump -uroot -p database > utf8.dump # this is bad

Better do:

mysqldump -uroot -p database -r utf8.dump

Note that when your MySQL server is not set to UTF-8 you need to do mysqldump --default-character-set=latin1 (!) to get a correctly e...

First do

ALTER DATABASE database_name CHARACTER SET "utf8";
ALTER DATABASE database_name COLLATE "utf8_unicode_ci";

After that, for each table:

ALTER TABLE table_name DEFAULT CHARACTER SET "utf8" COLLATE "utf8_unicode_ci";

This just changes the default character set / collation for each table. To convert them, you need:

ALTER TABLE tablename CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

From the shell:

ls -l | wc -l

When you get this while installing the raspell gem:

ERROR:  Error installing raspell:  
ERROR: Failed to build gem native extension.

You need some libraries:

sudo apt-get install libaspell-dev

When you get this error:

No word lists can be found for the language "de".

An aspell dictionary is missing. Install it with

sudo apt-get install aspell-de

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