===== GitHub.Com ====
<code bash>
ssh-keygen -t rsa -C "goodmama@daum.net"

Taekguui-MacBook:github mama$ ssh-keygen -t rsa -C "taekgu@gmail.com"
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/mama/.ssh/id_rsa): 
/Users/mama/.ssh/id_rsa already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/mama/.ssh/id_rsa.
Your public key has been saved in /Users/mama/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:ar39IO7YVRCFhOALYXSCRgbhqYyFnITh8m3uMSAGLd4 taekgu@gmail.com
The key's randomart image is:
+---[RSA 2048]----+
|=*oo= o. ooo.    |
|*+=. =  . ..     |
|=Bo . .   .      |
|B+.. . .   .     |
|++oEo . S   .    |
|.. +   o   .     |
|    + o o o      |
|   . + + = .     |
|    . ..= ...    |
+----[SHA256]-----+
Taekguui-MacBook:github mama$ pwd
/Users/mama/github
</code>