#!/bin/bash

file=$(mktemp ~/web/paste/XXXXXX)

[[ ! -z "$1" ]] && lang="-s $1"

cat - > ${file}.in
source-highlight -i ${file}.in -o ${file} ${lang}
rm ${file}.in

lftp -e "put -O /dir/to/paste ${file}; bye" \
     -u user,password sftp://example.com

echo "http://example.com/paste/${file##*/}"