Loop through all Let's Encrypt certificates

for CERTIFICATE in find /etc/letsencrypt/live/* -type d; do

CERTIFICATE=basename $CERTIFICATE

Combine certificate and private key to single file

cat /etc/letsencrypt/live/$CERTIFICATE/fullchain.pem /etc/letsencrypt/live/$CERTIFICATE/privkey.pem > /etc/haproxy/ssl/$CERTIFICATE.pem

done