Best practices setup for SSH client in OS X

osx-ssh-kickstart.sh

#!/bin/bash

# generates SSH key, if none
# TODO: suggests "good" key comment
# converts to encrypted key, in case existing key is not an encrypted one
# TODO: ensures that ~/.ssh/config defines that keys are added to agent upon (successfull) connection, and keychain is used for storing key password
# optionally, "fixes" Filezilla by auto-loading keys to SSH agent (otherwise only option is to run "ssh-add" manually or connecting to server in SSH first)

if [ ! -f ~/.ssh/config ]; then
   cat << EOF > ~/.ssh/config
UseKeychain yes
AddKeysToAgent yes
EOF
fi
chmod 0600 ~/.ssh/config

if [ ! -f ~/.ssh/id_rsa ]; then
    echo "SSH key was not found. No worries, we are going to walk you through the generation of the SSH key."
    ssh-keygen -t rsa -f ~/.ssh/id_rsa
else
    echo "Now we are going to check if your key is encrypted..."
    if ssh-keygen -p -P '' -N '' -f ~/.ssh/id_rsa > /dev/null 2>&1; then
       echo "Your SSH key ~/.ssh/id_rsa does not appear to be encrypted. We are going to encrypt it now."
       ssh-keygen -p -f ~/.ssh/id_rsa
    else
       echo "Your SSH key is an encrypted one. So far so good."
       read -p "Do you want to encrypt with a different passphrase? [y|n] " -n 1 -r
       echo    # (optional) move to a new line
       if [[ $REPLY =~ ^[Yy]$ ]]
       then
           # do dangerous stuff
           ssh-keygen -p -f ~/.ssh/id_rsa
       fi
    fi
fi

read -p 'Do you want to "fix" FileZilla by loading SSH keys with passphase already in keychain, to your SSH agent? [y|n] ' -n 1 -r
echo    # (optional) move to a new line
if [[ $REPLY =~ ^[Yy]$ ]]; then
  mkdir -p ~/Library/LaunchAgents/
  cat << EOF > ~/Library/LaunchAgents/ssh.add.a.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Label</key>
        <string>ssh.add.a</string>
        <key>ProgramArguments</key>
        <array>
                <string>/usr/bin/ssh-add</string>
                <string>-A</string>
        </array>
        <key>RunAtLoad</key>
        <true/>
</dict>
</plist>
EOF
else
  rm -rf ~/Library/LaunchAgents/ssh.add.a.plist
fi

echo "That's all, folks"