Shell script to use my github ssh keys to access my server and updates automatically daily =)

git-public-keys.sh

#!/usr/bin/env bash

# GIT_USERNAME=""
GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE="${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE:-${HOME}/.ssh/authorized_keys}"
GIT_PUBLIC_KEYS_START="## Start of git public keys"
GIT_PUBLIC_KEYS_STOP="## End of git public keys"

tmp_file=$(mktemp)
clean() {
  rm -f "$tmp_file" "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}.gitkeys"
}
trap clean EXIT SIGTERM SIGINT

GIT_URL="https://github.com/${GIT_USERNAME}.keys"

if [ ! -f "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}" ]; then
  echo "authorized_keys file could not be found on: '${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}' file path"
  exit 1
fi

if ! grep -q "${GIT_PUBLIC_KEYS_START}" "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}"; then
  echo "${GIT_PUBLIC_KEYS_START}" | tee -a "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}" > /dev/null 2> /dev/null
  echo "${GIT_PUBLIC_KEYS_STOP}" | tee -a "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}" > /dev/null 2> /dev/null
fi

start_line="$(grep --line-number "${GIT_PUBLIC_KEYS_START}" "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}" | awk -F ':' '{print $1}' | head -n 1)"
end_line="$(grep --line-number "${GIT_PUBLIC_KEYS_STOP}" "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}" | awk -F ':' '{print $1}' | head -n 1)"

if ! curl -fs "${GIT_URL}" --output "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}.gitkeys"; then
  exit 2
fi

tee "$tmp_file" < "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}" > /dev/null 2> /dev/null
{
  head -n "${start_line}" "${tmp_file}"
  cat "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}.gitkeys"
  tail -n "+${end_line}" "${tmp_file}"
} | tee "${GIT_PUBLIC_KEYS_AUTHORIZED_KEYS_FILE}" > /dev/null 2> /dev/null

Usage:

GIT_USERNAME="gtrabanco" ./git-public-keys.sh

Better usage with crontab and you will have synced ssh keys to access your remote servers =)

Important! Replace with your git username or you will be granting access to your terminal to me