Danny Denenberg

Automating Backups with Cron & GitHub

Back when I was using Ghost as my blogging platform, I had a problem. I wanted to keep my blog backed up, but I was too cheap to pay the extra $1 a month for Digital Ocean to do it for me.

Being me, I found a hacky way around paying.

I wrote a script to zip my ghost folder and push it up to my GitHub in some repo specifically for storing backups. Using cron, I made it run weekly. It worked great! With git’s version control, I could go through my previous backups, so it was just like how Digital Ocean might do it 👍.

To do this, make sure git is installed on your Linux/Unix system.

Then set your username and email in the git preferences through the terminal.

git config --global user.name "FIRST_NAME LAST_NAME"
git config --global user.email "[email protected]"

Next create an empty secret repo in your GitHub and clone it on your machine locally.

git clone https://github.com/dannydenenberg/mybackupsrepo.git

Make sure you can stay authenticated on your local device (you don’t have to enter your password to GitHub on every push up). You can use ssh keys to do this.

Make sure you have zip installed with sudo apt install zip, then write your bash script looking something like this (example from my Ghost blog):

zip /home/mybackupsrepo/mybackup.zip /var/www/ghost # zip the folder
cd /home/mybackupsrepo # go to the backups repo
git add . && git commit -m "$(date)" && git push origin master # commit, push
sudo rm -Rf /home/mybackupsrepo/mybackup.zip # clean

Make it executable: chmod +x /home/whereveryoustoredthisbashscript

And add it to your cronjobs. To edit the cronjobs running, execute crontab -e (the actual file is stored in /var/spool/cron).

Here is a quick reference for creating new cronjobs and how to schedule them properly:

# crontab -e
MAILTO=[email protected]

# For details see man 4 crontabs

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed

# backup using the rsbu program to the internal 4TB HDD and then 4TB external
01 01 * * * /usr/local/bin/rsbu -vbd1 ; /usr/local/bin/rsbu -vbd2

# Set the hardware clock to keep it in sync with the more accurate system clock
03 05 * * * /sbin/hwclock --systohc

# Perform monthly updates on the first of the month
# 25 04 1 * * /usr/bin/dnf -y update