It's Luis' blog

How To Back Up Files to S3 And Delete Them Using Bash

April 03, 2022

You have a situation. Your machine is filling up with files - could be logs, could be important data that you no longer need after sometime, and you need to get rid of them. You don’t want to delete them permanently because you’re unsure if you’re going to need them in the future. Why not back them up to S3, which is very cheap, and at the same time delete them from the local machine?


time_in_the_past=604800 # 1 week in seconds

current_time=$(date +"%s")
while read -d '' file; do
  mtime=$(stat -c %Y $file)

  if [ "$difference" -gt "$time_in_the_past" ]; then
    echo "Backing up $file"
    aws s3 cp $file s3://$bucket_name$bucket_path && unlink $file
done < <(find $directory -type f -print0)

This script will read the files in a directory, check that they’re older than a specified time, upload them to S3 and if successfully, delete them from the local machine. This script assumes you installed and configured the AWS CLI.

There are 4 variables at the top that control how it will behave:

  • timeinthe_past is a week in seconds, but you can change this to any value.
  • directory is the directory where the backups will happen.
  • bucket_name The bucket name in which the files will be uploaded. (a-z0-9_-)
  • bucket_path The path inside the bucket where the files will be placed.

You can save this file as and then run it every X amount of time using crontab. To open crontab, you can run

crontab -e

Then choose your preferred editor (I usually go for nano). Then place the crontab line at the end:

30 6 * * sun /path/to/

The 30 6 * * sun means every sunday at 6:30 am. You can visualize cron expressions with this amazing tool called cron guru.