Comandos do vídeo https://www.youtube.com/watch?v=NUjUBUd3nBA

cmd.sh

# verificando o hostname
echo $HOSTNAME

# gerando a chave SSH
ssh-keygen -t ed25519 -C "seu-email@exemplo.com" -f ~/.ssh/id_$HOSTNAME

# keychain do macOS
eval "$(ssh-agent -s)"
ssh-add --apple-use-keychain ~/.ssh/id_$HOSTNAME

# Arquivo do .ssh/config.d
Host github.com
  AddKeysToAgent yes
  UseKeychain yes
  IdentityFile ~/.ssh/id_<HOSTNAME>
  IdentitiesOnly yes

# copiando a chave pública no macOS
cat ~/.ssh/id_$HOSTNAME.pub | pbcopy

# copiando a chave pública no Linux ou FreeBSD
cat ~/.ssh/id_$HOSTNAME.pub | xclip -selection clipboard

# copiando a chave pública no Wayland
cat ~/.ssh/id_$HOSTNAME.pub | wl-copy

# testando a chave
ssh -T git@github.com

# keychain no Ubuntu
sudo apt install keychain

# keychain no Fedora
sudo dnf install keychain

# keychain no Arch
sudo pacman -S keychain

# keychain no FreeBSD
doas pkg install keychain

# adicionando no `~/.bashrc`, `~/.zshrc` ou `~/.profile`:
eval "$(keychain --eval --quiet ~/.ssh/id_$HOSTNAME)"

# gera a chave GPG
gpg --full-generate-key

# lista as chaves secretas
gpg --list-secret-keys --keyid-format LONG

# copia a chave - ver outros sistemas acima
gpg --armor --export SEU_KEY_ID | pbcopy

# instalando o pinentry no macOS
brew install pinentry-mac

# configurando o `~/.gnupg/gpg-agent.conf` no macOS
pinentry-program /opt/homebrew/bin/pinentry-mac

# configurando o `~/.gnupg/gpg-agent.conf` no Linux ou FreeBSD
pinentry-program /usr/local/bin/pinentry-qt

# matando o agente, para recarregar
gpgconf --kill gpg-agent