If you should ever lose your public key, but still have your private key, you can always compute your public key from your private key.
The following command prints your public key to stdout (with
id_rsa being your private key file, e.g. under
ssh-keygen -y -f id_rsa
Or just pipe directly to a file with:
ssh-keygen -y -f id_rsa > id_rsa.pub
Now you can redistribute your public key where ever you need it.
Any questions? Please comment.