#!/bin/bash
# Simple bash client for linux

if [ "$#" != 3 ] ||  { [ "$1" != "download" ] && [ "$1" != "upload" ];}
then echo "Usage: $0 [download|upload] FILENAME SERVERNAME"; exit 1; fi

f=$2; s=$3

if [ "$1" = "download" ]
then
  c=$(dig +short txt "$f".count."$s"|tr -d \")
  for i in $(seq 0 "$c"); do echo -n "$(dig +short txt "$f"."$i"."$s"|tr -d \")"; done | base64 -d > "$f"
else
  i=0; d=$(base64 -w 0 < "$f"); id=$(sha256sum "$f" | cut -d" " -f1 | base64 -w 0 | cut -c1-6)
  while true; do
    u=".$i-${id}u.$s"; ((i++)); x=$((63-${#u}))
    if [ $x -lt ${#d} ]
    then p=${d:0:$x}; d=${d:$x}; dig +short txt "$p$u"
    else dig +short txt "$d$u"; exit 0
    fi
  done
fi

# Minimal working example for download in case you have to type it all manually
mwe() {
  f=$1; s=$2; c=$(dig +short txt "$f".count."$s"|tr -d \")
  for i in $(seq 0 "$c"); do echo -n "$(dig +short txt "$f"."$i"."$s"|tr -d \")"; done | base64 -d > "$f"
}