Use this command to convert private key to public key.

ssh-keygen -y -f dec15a.pem > dec15a.pub

Now upload the new public key to list of keys on Amazon so that you can connect to your instances in that region using the same pem key.

The 8th column of ps aux command will list the status of the process.

ps aux | awk '{if ($8 ~ "D") print $0}'

Here is a list of the various process statuses and what they mean:

D – Uninterruptible sleep (usually a critical system process, a process that cannot be killed without rebooting)
R – Running
S – Interruptible sleep (waiting for an event to complete)
T – Stopped
Z – Defunct (“zombie”) process

It is possible to use password to connect to AWS

1) change config file
sudo vi /etc/ssh/sshd_config

PermitRootLogin yes
PasswordAuthentication yes

2) restart
sudo service ssh restart

3) add a password
sudo passwd root

4) ssh without key
ssh root@xxx.com

Upgrade from 14.04 to 15.04 is a 2 step journey.

sudo nano /etc/update-manager/release-upgrades
change the value to normal

And then use this command twice!
sudo do-release-upgrade

You can check your ubuntu version:

lsb_release -a
Description: Ubuntu 15.04

Here is how to install Libre office on centOS

64 bit
wget http://download.documentfoundation.org/libreoffice/stable/4.4.4/rpm/x86_64/LibreOffice_4.4.4_Linux_x86-64_rpm.tar.gz

32 bit
wget http://download.documentfoundation.org/libreoffice/stable/4.4.4/rpm/x86/LibreOffice_4.4.4_Linux_x86_rpm.tar.gz

tar xvf LibreOffice_4.4.4_Linux_x86_rpm.tar.gz

rpm -Uvh LibreOffice_4.4.4.3_Linux_x86_rpm/RPMS/*.rpm

Here is how you can open and copy files from an iso image.

mkdir /mnt/iso
mount -t iso9660 -o loop /root/Downloads/ubuntu-15.04-desktop-i386.iso /mnt/iso/

ls /mnt/iso/

Create a new repository on the command line

touch README.md
git init
git add README.md
git commit -m "first commit"
git remote add origin git@github.com:shantanuo/vivac.git
git push -u origin master

Push an existing repository from the command line

git remote add origin git@github.com:shantanuo/vivac.git
git push -u origin master

on Remote server:
ssh -fN -R 7000:localhost:22 username@yourMachine-ipaddress

Now do an ssh connection request from your machine to your own machine at port 7000:
ssh username@localhost -p 7000

Here is a simple tip that will avoid RSA key fingerprint authentication. Edit /etc/ssh/ssh_config for global configuration or ~/.ssh/config for user-specific configuration.

Host 192.168.0.*
StrictHostKeyChecking no
UserKnownHostsFile=/dev/null

Here are a few ways to kill mysql process.

mysqladmin shutdown
kill -TERM nnnn
killalll mysqld
kill -TERM `pidof mysqld`
kill -TERM `cat /var/run/mysqld.pid`