Rsync is a very powerful  backup tool. It can significantly speed up backup process and minimize amount of data transferred during synchronization. In most cases rsync is used to make incremental backups, but it also has another interesting option which gives you ability to keeping old versions of files on backup server. Mentioned option is ‘–backup’ or simply ‘-b’. Continue Reading

Some kinds of software require only one format of SSL certificates. This is the way how you can convert certificates between two popular formats (PEM and DER).

Use ‘openssl’:

openssl x509 -inform DER -in der-cert.crt -outform PEM -out pem-cert.pem

And vice versa:

openssl x509 -inform PEM -in pem-cert.pem -outform DER -out der-cert.crt


This short article describe how to reset lost root password on Linux system. IMPORTANT: This method require physical access to the machine.

On GRUB screen select normal boot option:

1Press ‘e’ to edit selected option. You will see short GRUB code.


Search for the line starting with “linux /boot/vmlinuz…” or similar depending of Linux distribution. This is the place where kernel and rootfs is selected. Change ‘ro’ option to ‘rw’ and add: Continue Reading