Ubuntu: Installing pg gem

After updating my Ubuntu from 14.04 to 15.04, I ran across problem running "bundle install". It told me to install the pg gem manually. I did, but I got the error below. To fix the problem, I had to install libpg-dev before running bundle install again.

sudo apt-get install libpq-dev

Error

Building native extensions.  This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

    /home/irobot/.rvm/rubies/ruby-2.2.0/bin/ruby -r ./siteconf20150721-26806-ml2lou.rb extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/home/irobot/.rvm/rubies/ruby-2.2.0/bin/$(RUBY_BASE_NAME)
    --with-pg
    --without-pg
    --enable-windows-cross
    --disable-windows-cross
    --with-pg-config
    --without-pg-config
    --with-pg_config
    --without-pg_config
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/lib

extconf failed, exit code 1

Gem files will remain installed in /home/irobot/.rvm/gems/ruby-2.2.0/gems/pg-0.18.2 for inspection.
Results logged to /home/irobot/.rvm/gems/ruby-2.2.0/extensions/x86_64-linux/2.2.0/pg-0.18.2/gem_make.out

Resource:

http://stackoverflow.com/questions/6040583/cant-find-the-libpq-fe-h-header-when-trying-to-install-pg-gem

Basic markdown

Link

[Link name](www.url.com)

Reference link
[The New York Times][NY Times]
[ny times]: http://www.nytimes.com/ 

Headers

# Header 1
## Header 2
### Header 3

Emphasis
*italicize*
**bold**
_**italicize and bold**_  or __*really strong emphasis*__


List
Unordered list - dash and space
- Item 1
- Item 2
  - Nested item needs 2 spaces
    - 2 spaces for each 'nest'

Order list - only need a number and a period and space
1. Item 1
1. Item 2 
1. Item 3

Code
`inlined code`

Code block may needs new line before and after block.

```java
public void static main(String[] args) {

}
```

Image


![](./pic/pic1_50.png =100x20)

Install Django for Ubuntu

Assuming you have python installed, you can install Django with this command:

• sudo apt-get install python-django

You can check that Django is installed by checking its version:

• python -c "import django; print(django.get_version())"

Ubuntu: Remapping Right Ctrl with Right Alt

Ubuntu uses xkb to handle its keyboard mapping. You can read more about it here:

• https://wiki.archlinux.org/index.php/Keyboard_configuration_in_Xorg

Because I use the CTRL key a lot, I want it to be easier to access. Since I always use the ALT key with my left hand, I decided to switch the right ALT key with the Right CTRL key.

To do this, I opened 10-evdev.conf as an admin:

• sudo pico /usr/share/X11/xorg.conf.d/10-evdev.conf

and added the following to the file:

Section "InputClass"
        Identifier "system-keyboard"
        MatchIsKeyboard "on"
        Option "XkbLayout" "us"
        Option "XkbModel" "pc104"
        Option "XkbOptions" "ctrl:rctrl_ralt,ctrl:ctrl_ralt"
EndSection

Restart your computer to verify your changes.

As you can see, most of the setting is for the keyboard. The most important thing is the second to last line, Option "XkbOptions" "ctrl:rctrl_ralt,ctrl:ctrl_ralt". This states that I want to right CTRL key as right ALT key and vice versa. You see more xkb options in the base file (start on line 692):

• /usr/share/X11/xkb/rules/base.lst

I haven't tried it, but you can probably switch the caps lock with the control key with ctrl:swapcaps

Resource:

• Keyboard Configuration in Xorg
• Hacking Your Linux Keyboard With XKB

Ubuntu hangs on boot on Asus U46E

Recently, I installed Ubuntu on my Asus laptop, but it keeps hanging on the start up screen. It seems like Asus laptop has a problem with this. After reading several options, this one works for me:

1. Go into your BIOS
2. Select "Advance" using the right arrow button
3. Select "VT-d" by pressing the down arrow button
4. Press "Enter"
5. Select "Disable"
6. Press "F10" to exit the screen
7. Select "Yes" to save

Note: You can read on VT-d on Intel blog to see if that's the best option for you.

If that doesn't work, you may find these solutions helpful:

1. Ubuntu 10.10 [64 Bit] hang on boot 
2. Ubuntu 12.10 boot hangs on purple screen 
3. Ubuntu hangs at purple screen