Allows multiple GitHub users to use the same computers using individual SSH keys

github.sh

#!/bin/sh

# This script creates an SSH key for use on GitHub

# Step 1: Copy and paste this github() function into the ~/.zshrc file
github() {
  eval "$(ssh-agent -s)"
  ssh-add ~/.ssh/$1
  email=`cat ~/.ssh/$1.email`
  git config --global user.name $1
  git config --global user.email $email
}
# Step 2: Source .zshrc by running this in the terminal:
#         source ~/.zshrc
# Step 3: Run this script passing the the GitHub username and
#         email address associated with the GitHub account (see usage)
# Step 4: Apply credentials locally by running this in the terminal:
#         github github-username

usage() {
  echo ""
  echo "This script creates an SSH key for use on GitHub."
  echo ""
  echo "./github.sh github-username github-email"
  echo ""
}

createkey() {
  echo $2 >> ~/.ssh/$1.email
  ssh-keygen -t rsa -b 4096 -f ~/.ssh/$1 -C $2
  cp ~/.ssh/$1 .
  cp ~/.ssh/$1.pub .
  cp ~/.ssh/$1.email .
  pbcopy < ./$1.pub
  echo "Your public key has been copied to your clipboard."
  echo "Go to https://github.com/settings/keys and create a new SSH key."
  echo "Name the key 'EDA' and use the contents of your clipboard."
}

if [ "$#" -lt 2 ]; then
  usage
else
  createkey $1 $2
fi

This script copies the public and private key files (including the username.email file) to the current folder. So if you run this script from a thumb drive, it's easier to collect all the keys in one place to easily transfer them to the .ssh folders on all shared computers.