ppk to pem

In WINDOWS machines use the following steps

Start putty gen tool in windows
Look at ACTIONS section and choose "Load" button
Browse through the folders to pull the ppk file fo which you need to create a pem file
Key passphrase is optional and cick YES to ignore
From the menu , choose Conversions  --> Drop down --> Export OpenSSH Key.
Just say 'Yes' for warning of not entering passphrase
Save the file as <xyz>.pem


In LINUX environments use the following steps
1. If puttygen not installed 
  sudo apt-get install putty-tools 
2. Convert ppk to pem 
  puttygen server-key.ppk -O private-openssh -o serverpem-key.pem
3. Change permission of the pem file.
  chmod 400 serverpem-key.pem