Mac generate (more than one) pkk file from private key

You can generate your (first) ssh key with:
$ ssh-keygen -o -a 100 -t ed25519 -f ~/.ssh/{typeNameForYourKeyHere} -C "{yourName@yourWorkStation}"
Then you can see the key
$ cat < ~/.ssh/{typeNameForYourKeyHere}
Now for FileZilla you might need the pkk file
Therefor you need putty
$ brew install putty
$ puttygen {typeNameForYourKeyHere} -O private -o {typeNameForYourKeyHere}.ppk
While most people will use id_ed25519 or id_rsa as filenames, when using multiple ssh keys it can be useful to give more specific names at {typeNameForYourKeyHere}. When running the above for a second key, it is important to use another name.
I you use multiple keys you can put a ‘config’ file in your .ssh/ folder and assign different keys for different purposes, like so:
$ touch ~/.ssh/config $ nano ~/.ssh/config
# github host github.com user usernameGithub Identityfile ~/.ssh/{typeNameForYourKeyHere} # bitbucket host bitbucket.org user usernameBitbucket Identityfile ~/.ssh/{typeNameForYourKeyHere}