In Ubuntu, user “root” won’t show up as an options to login, which you need to adjust the Ubuntu to allow login as “root”.
Run this command below in your terminal (as normal user with sudo):
sudo passwd root
sudo sh -c 'echo "greeter-show-manual-login=true" >> /etc/lightdm/lightdm.conf'
Reboot and then you should be able to login as root using graphical user login.
If you start your Ubuntu and it display a grub shell to you, you can run this command below to fix it:
grub-rescue> prompt
ls
set prefix=(hdX,Y)/boot/grub
set root=(hdX,Y)
set
ls /boot
insmod /boot/grub/linux.mod
linux /vmlinuz root=/dev/sdXY ro
initrd /initrd.img
boot
* Ensure that you entered correct partition (e.g. hd0,1) for hdX,Y. If not, than your grub will be messed.
References :
http://superuser.com/questions/181733/how-can-i-restore-grub-without-a-live-cd1
http://www.linux.com/learn/tutorials/776643-how-to-rescue-a-non-booting-grub-2-on-linux
Recently, I want to install MongoDB in my Rasp Pi. But unfortunately, I can’t install MongoDB via apt-get because Rasp Pi is using ARM architecture.
Maybe we can compile it from source code. Yes. We can. But MongoDB source is very x86 specific, meaning the newest version isn’t available for ARM architecture.
But… Thanks to this owsem patches from Per Ola Ingvarsson on Github at https://github.com/skrabban/mongo-nonx86, now we can compile MongoDB on Rasp Pi. Yeay!
So, to build MongoDB on your RaspberryPi:
Install the required packages:
sudo apt-get install git-core build-essential scons libpcre++-dev xulrunner-dev libboost-dev libboost-program-options-dev libboost-thread-dev libboost-filesystem-dev
Clone the Github repo:
git clone https://github.com/skrabban/mongo-nonx86
Now let’s compile it! (*Note that these two steps take a very very long time on a Rasp Pi. So I left mine for 1 day for this.)
cd mongo-nonx86 scons sudo scons --prefix=/opt/mongo install
Done! You have MongoDB installed on your Rasp Pi.
This will install mongo in /opt/mongo, to get other programs to see it, you can add this dir to your $PATH:
PATH=$PATH:/opt/mongo/bin/ export PATH