#!/bin/sh

busrv="user@servertoholdbackups"
butgt="user@servertobebackedup"

# backup directory
budir="/path/to/backupdir/on/busrv/"
# directory to be backed up
butgtdir="/path/to/dir/on/butgt"
# prefix name
bupfx="someprefix"
# secret key
bukey="/path/to/file/containing/secretkey/on/busrv"

# pipes
todar="/tmp/todar"
toslv="/tmp/toslv"
[[ -e $todar ]] || mkfifo $todar
[[ -e $toslv ]] || mkfifo $toslv

ssh $busrv 'dar_slave `find '$budir' -not -size 0 -name "'$bupfx'*" 2>/dev/null | sort | tail -n1 | sed "s/\..*\.dar$//"`' < $toslv > $todar &
ssh $busrv 'ssh '$butgt' "dar -c - -A - -i '$todar' -o '$toslv' -z -m 150 -R '$butgtdir' -q -J :"`cat '$bukey'`" -K :"`cat '$bukey'` > `date "+'$budir'/'$bupfx'-%y-%m-%d_%H-%M.1.dar"`'