Convert PPK putty keys to openssh
This is one I constantly forget and have to look up over and over, probably due to not having to do it very often. To convert and install keys from your Putty PPK to linux ( Ubuntu ).
Install putty with: sudo apt-get install putty
Create the public key file:
puttygen /path/to/puttykey.ppk -L > ~/.ssh/id_rsa.pub
Create the private key file:
puttygen /path/to/puttykey.ppk -O private-openssh -o ~/.ssh/id_rsa
You should now be able to log into an SSH server using your private key. To install your public key simply copy from ~/.ssh/id_rsa.pub on your local machine to ~/.ssh/authorized_keys on the remote server;