$ ssh-keygen
Enter file in which to save the key (/home/petr/.ssh/id_rsa): /home/petr/my.key
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/petr/my.key.
Your public key has been saved in /home/petr/my.key.pub.
The key fingerprint is:
SHA256:t7oRcfThgNf5w8kXl+pg6Xgso/BJtBDt4T42vFUpZ7U petr@pc
The key's randomart image is:
+---[RSA 2048]----+
| . .o... .|
| . o...+oo o.|
| + o.. *+o.o|
| . + + O E* .|
| = S @ o o |
| . O B = . |
| = O = |
| = o |
| o. |
+----[SHA256]-----+
To use this key you have 2 choices: run command
ssh -i ~/my.key posvic.eu
or edit SSH config file and specify IndetityFile for host. Then is no need to use parameter -i.
# ~/.ssh/config
Host posvic.eu
IdentityFile ~/my.key
ssh posvic.eu