Script to emulate time machine snapshot based backup.

snapshot-backup.sh

#!/bin/bash

## my own rsync-based snapshot-style backup procedure
## (cc) marcio rps AT gmail.com
## modified by github.com/maca
lock=/tmp/snapshot-lock
if [ -f $lock ] ; then
  echo "snapshot: a lock file seems to exist $lock"
  exit
fi

touch $lock

# config vars
host=<your-backup-server>
port=22

src="/home/$(whoami)/" #dont forget trailing slash!
snap="/backup/snapshots/$(whoami)"
opts="-zia --delete --delay-updates"
minchanges=200

# run this process with real low priority
ionice -c 3 -p $$
renice +12  -p $$

# sync
ssh -p $port $host "mkdir -p $snap"
rsync $opts --rsh="ssh -p$port" $src $host:$snap/latest | ssh -p $port $host "cat - >> $snap/rsync.log"

# check if enough has changed and if so
# make a hardlinked copy named as the date
datetag=$(date +%y-%m-%d-%h-%m)
ssh -p $port $host "
  sleep 20
  count=\`wc -l $snap/rsync.log | cut -d ' ' -f1\` 
  if [ \$count -gt $minchanges ] ; then
     if [ ! -e $snap/$datetag ] ; then
        cp -al $snap/latest $snap/$datetag
        mv $snap/rsync.log $snap/$datetag
     fi
  fi
"

rm $lock