How do I create custom backup script?

Question

I am going to make a shell script file which compress all files from the home directory, but the tar is not running after I have changed the permissions.

#!/bin/bash
tar -zxvf homefiles.tar.gz /home/

Answer 1

It is not clear: What permissions have you changed? But I will ignore this message :)

Normally system users doesn't have write permissions outside their own home directory, that by default is /home/<user>. Also user-A can't read most of the files of user-B. So according to the path in your question, to backup all files and directories located in /home, you should run the command with root's privileges, by using sudo.

In addition you are using wrong option - x instead c - use tar --help:

tar -cf archive.tar foo bar  # Create archive.tar from files foo and bar.
tar -xf archive.tar          # Extract all files from archive.tar.

So the right command should be one of these:

sudo tar -zcvf /home/homefiles.tar.gz /home/ --exclude=/home/homefiles.tar.gz # the backup will be created in the directory `/home`
tar -zcvf /home/<user>/homefiles.tar.gz /home/<user> --exclude=/home/<user>/homefiles.tar.gz

Here is an extended example for you:

How to create custom backup script

Let's assume along with the /home directory there are also Apache and MySQL servers and we want to make more complete backup of the system.

1. Create a file named mybackup; make it executable; locate it in /usr/local/bin to be accessible as shell command system wide. Create a directory where the backup files will be stored:

sudo touch /usr/local/bin/mybackup && sudo chmod +x /usr/local/bin/mybackup
sudo mkdir /var/backup

Paste the following script as content of the file /usr/local/bin/mybackup and save it:

#!/bin/bash

## Get the current date as variable.
TODAY="$(date +%Y-%m-%d)"

## Delete backup files older than 2 weeks before create the new one.
find /var/backup/ -mtime +14 -type f -delete

## MySQL Section. The first line is if you are using `mysqldump`,
## the next line is for `automysqlbackup`. I'm using both.
mysqldump -u'root' -p'<my-pwd>' --all-databases | gzip > /var/backup/mysql-all-db.sql.gz
automysqlbackup

## Tar Section. Create a backup file, with the current date in its name.
## Add -h to convert the symbolic links into a regular files.
## Backup some system files, also the entire `/home` directory, etc.
## --exclude some directories, for example the the browser's cache, `.bash_history`, etc.
tar zcvf "/var/backup/my-backup-$TODAY.tgz" \
/etc/hosts /etc/sudoers* /var/spool/cron/crontabs /etc/cron* \
/etc/apache2 /etc/letsencrypt /etc/php/7.0/apache2/php.ini \
/etc/phpmyadmin/apache.conf /etc/mysql/debian.cnf \
/etc/ssh/sshd_config* /etc/pam.d/sshd \
/usr/local/bin \
/var/backup/mysql-all-db.sql.gz /var/lib/automysqlbackup/latest/*.sql.gz \
/root \
/home \
/var/www \
--exclude=/home/<some-user>/.composer --exclude=/home/<some-user>/.npm

## MySQL Section - remove the DB backup files, if you want:
#rm /var/lib/automysqlbackup/latest/*.sql.gz
rm /var/backup/mysql-all-db.sql.gz

• If this is a VPS, maybe you would want to access your backup file from Internet through the web browser. In this case we could encrypt the file for additional security. If you are fan of 7zip add some command as the next to the bottom of the script:

  rm /var/www/html/the-location/*
  7za a -tzip -p'<my-strong-pwd>' -mem=AES256 "/var/www/html/the-location/my-backup-$TODAY.tgz.7z" "/var/backup/my-backup-$TODAY.tgz"
  

• If this is a desktop, maybe you will want to exclude the entire Downloads directory for each user. You could exclude also all files larger than or/and excluding certain file's extensions.

• Please note all commands used above are located in /bin or /usr/bin that are listed into the default $PATH of Cron. If you are intend to use Cron job to automate the task and you have commands (scripts) that are located outside of these directories, you should use /the/full/path/to/the/script :)

2. To crate a backup manually, now you can use this command:

sudo mybackup

3. To automate the the task you can add a new entry in root's crontab by the command sudo crontab -e. For example to execute the script every night at 1:15 the Cron job definition should be:

15 1 * * * /usr/local/bin/mybackup > /var/log/mybackup-cron.log 2>&1

• this will create also the log file /var/log/mybackup-cron.log that will contain and the error messages 2>&1 if there are any. Read the log periodically to be sur everything works fine.

Alternatively, I would prefer to create a script in /etc/cron.daily/:

sudo touch /etc/cron.daily/mybackup && sudo chmod +x /etc/cron.daily/mybackup

The content of the file should be something as this:

#!/bin/sh
test -x /usr/local/bin/mybackup || exit 0
echo -e "*** Log Begin $(date +%Y-%m-%d) ***\n" >> /var/log/mybackup-cron.log
/usr/local/bin/mybackup > /var/log/mybackup-cron.log 2>&1
echo -e "*** Log End $(date +%Y-%m-%d) *** \n" >> /var/log/mybackup-cron.log

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Update:

The above script could be found in the GitHub repository, named Simple Backup Solutions.