ssh config

ssh-config.md

.ssh/config

Host *
  # select if ssh key should be added to ssh agent
  AddKeysToAgent no
  # only if supported
  IgnoreUnknown UseKeychain
  # select if key pass phrase should be added to key chain
  UseKeychain no
  
Host *-screen
  RequestTTY force
  RemoteCommand screen -d -R

Host h home h-screen
  User dev
  HostName dev.home.net
  IdentityFile ~/.ssh/id_dev.home.net

Host w work w-screen
  User dev
  HostName dev.work.net
  IdentityFile ~/.ssh/id_dev.work.net

Host github.com
  HostName github.com
  User git 
  IdentityFile ~/.ssh/id_github.com

Host github.work.com
  HostName github.work.com
  User git 
  IdentityFile ~/.ssh/id_github.work.com

SSH options in macOS Sierra

AddKeysToAgent	UseKeychain	Meaning	Effect
yes	yes	Store key in ssh agent and key passphrase in key chain	Enter passphrase once
yes	no	Store key in ssh agent but do not store key passphrase in key chain	Enter passphrase once for every reboot
no	no	Do not store key in ssh agent and do not store key passphrase in key chain	Enter passphrase everytime