keep multiple snapshots so that you can recover files after you delete them yourself.

#!/bin/sh

AWS_ACCESS_KEY_ID=<>

AWS_SECRET_ACCESS_KEY=<>

BUCKET=<>

DIR=<>

S3SYNC=/usr/bin/s3sync.rb

DAYS_TO_KEEP_BACKUPS=30

# colons in path confuse s3sync

DATE=$(date +%F_%H-%M-%S)

NEWEST=$(/bin/ls -r $DIR | grep -v current | head -1)

# copy the newest copy of files into a new directory, creating hardlinks instead of duplicate files

cp -al $DIR/$NEWEST/ $DIR/$DATE/

# sync the s3 bucket against the new directory

$S3SYNC --recursive --make-dirs --delete --no-md5 -v $BUCKET: $DIR/$DATE/ 2>&1 | grep -v 'Could not change owner'

# update the "current" symlink link

test -e $DIR/current && rm $DIR/current

ln -sf $DIR/$DATE $DIR/current

# remove snapshots older than DAYS_TO_KEEP_BACKUPS days

find $DIR -maxdepth 1 -type d -mtime +$DAYS_TO_KEEP_BACKUPS -print0 | xargs -0 --no-run-if-empty rm -rv