Puttygen generate PPK from pem

Here is a example how to convert .pem to .ppk using Ubuntu.First you need to install package putty-tools

sudo apt-get install putty-tools
After install, all you really need to do is this:puttygen key.pem -o key.ppk
But.. with -P switch you can set passphrase for extra security, this is recommended and easy to do:puttygen key.pem -o key.ppk -P -C "My server key"
It is also recommended to set comment for your key using -C switch, because this string will be prompted to you when you are entering your passphrase.

Note that you can also change passphrase afterwards by using -P switch

m@box:~/Downloads$ puttygen -P key.ppk Enter passphrase to load key: Enter passphrase to save key: Re-enter passphrase to verify: