gen_gpg_key.sh

#!/usr/bin/env bash

# Set variables for your name and email
FullName=""
EmailAddress=""

# Parse command line options
while getopts ":n:e:c:" opt; do
  case $opt in
    n)
      FullName=$OPTARG
      ;;
    e)
      EmailAddress=$OPTARG
      ;;
    c)
      KeyComment=$OPTARG
      ;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      ;;
  esac
done

# Check if variables are still empty and show help message
if [[ -z $FullName || -z $EmailAddress ]]; then
  echo "Usage: gen_gpg_key -n <name> -e <email> -c [comment]"
  echo "Comment is optional."
  exit 1
fi

if [[ -z $KeyComment ]]; then
  KeyComment="Code Signing Key for $FullName <$EmailAddress>"
fi

# Generate the GPG key with ECC and Curve 25519
gpg --batch --generate-key <<EOF
    Key-Type: RSA
    Key-Length: 4096
    Subkey-Type: RSA
    Subkey-Length: 2048
    Name-Real: $FullName
    Name-Email: $EmailAddress
    Expire-Date: 0
    %no-protection
    %commit
EOF


# List the generated keys
GPG_KEY_DATA=$(gpg --list-secret-keys --keyid-format LONG "$EmailAddress")
FOUND_KEYS=$(echo "$GPG_KEY_DATA" | grep  -E 'sec   rsa4096/[^ ]+' | awk -F 'rsa4096/' '{ print $2; }' | awk '{ print $1; }' )
TOTAL_KEYS_FOUND=$(echo "$FOUND_KEYS" | wc -l)

if [[ $TOTAL_KEYS_FOUND -gt 1 ]]; then
  echo "Found more than one key. Please delete the keys and try again."
  echo "$GPG_KEY_DATA"
  exit 1
fi

GPG_KEY_ID=$(echo "$FOUND_KEYS" | awk '{ print $1; }')

echo "Your GPG key ID is: $GPG_KEY_ID"
echo

# Export the GPG public key
gpg --armor --export "$GPG_KEY_ID"

echo
echo "Copy the above GPG public key and add it to your GitHub account."

# Configuring Git to use the GPG key
git config --global user.signingkey "$GPG_KEY_ID"
git config --global commit.gpgsign true

echo "Git is now configured to sign commits using this GPG key."