Convert OpenSSH private key to PEM file format

Assuming that your ssh private key is located at ~/.ssh/id_rsa. We will convert this file to the PEM format.

# Change dir to home directory
cd ~

# Make a copy of the private key and store the copy in the home directory
cp ~/.ssh/id_rsa ~/id_isa_copy

# Convert the copy to the PEM format
ssh-keygen -p -f ./id_isa_copy -m PEM

After this, the file at ~/id_rsa_copy is in the PEM format.