Usually a public SSH key is generated at the same time as a private key.
Unlike a private SSH key, it is acceptable to lose a public key as it can be generated again from a private key at any time.
In this small note i am showing how to create a public SSH key from a private one using ssh-keygen command-line tool.
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Get Public SSH Key from Private
Use the following command to read a private SSH key from a file and print a public key:
$ ssh-keygen -y -f <keyfile>
Short explanation:
| Option | Description |
|---|---|
-y |
Read a private OpenSSH format file and print an OpenSSH public key to stdout |
As an example, let’s generate a public SSH key from a private key ~/.ssh/id_rsa and save it to the file ~/.ssh/id_rsa.pub:
$ ssh-keygen -y -f ~/.ssh/id_rsa > ~/.ssh/id_rsa.pub