Convert .ppk file to .pem file & connect to remote server via SSH - Linux

First install the putty tools, if you don`t have on your Linux installation.

sudo apt-get install putty-tools

Generate the .pem file from .ppk file with the following command.

puttygen ppkkey.ppk -O private-openssh -o pemkey.pem

Place the new generated pemkey.pem file in your ~/.ssh directory.

cp pemkey.pem ~/.ssh

Set the proper permissions for .pem file.

chmod 400 pemkey.pem

To connect via SSH with new .pem file, use below command.

ssh -i pemkey.pem user@server_ip

To convert .pem file to .ppk file,

puttygen pemKey.pem -o ppkKey.ppk -O private

-o means where to write out the converted putty private key & -O private means the output will be in a PuTTY private key format.