Databases, Systems & Networks

To clone a Debian installation, use the apt-clone utility. It’s available (as a separate package, not part of the default installation) in Debian since wheezy and in Ubuntu since 12.04. On the existing machine, run

apt-clone clone foo

This creates a file foo.apt-clone.tar.gz. Copy it to the destination machine, and run

apt-get install apt-clone
apt-clone restore foo.apt-clone.tar.gz

If you’re working with an old system where apt-clone isn’t available, or if you just want to replicate the list of installed packages but not any configuration file, here are the manual steps.

• On the source machine:

cat /etc/apt/sources.list /etc/apt/sources.list.d >sources.list
pkg --get-selections >selections.list
apt-mark auto >auto.list

• On the target machine:

cp sources.list /etc/apt/
apt-get update
/usr/lib/dpkg/methods/apt/update /var/lib/dpkg/
dpkg --set-selections <selections.list
apt-get dselect-upgrade
xargs apt-mark auto <auto.list

I believe that you’re affected by an incompatible change in dpkg that first made it into wheezy. See bug #703092 for background.

The short story is that dpkg --set-selections now only accepts package names that are present in the file /var/lib/dpkg/status or /var/lib/dpkg/available. If you only use APT to manage packages, like most people, then /var/lib/dpkg/available is not kept up-to-date.

After running apt-get update and before running dpkg --set-selections and apt-get -u dselect-upgrade, run the following command:

apt-cache dumpavail >/tmp/apt.avail
dpkg --merge-avail /tmp/apt.avail

From jessie onwards, you can simplify this to

apt-cache dumpavail | dpkg --merge-avail

Alternatively, run

/usr/lib/dpkg/methods/apt/update /var/lib/dpkg/

or even simpler

apt-get install dctrl-tools
sync-available

Another simple method that doesn’t require installing an additional package but will download the package lists again is

dselect update

See the dpkg FAQ for more information. (This is mentioned in the dpkg man page, but more in a way that would remind you of the issue if you were already aware, not in a way that explains how to solve the problem!)

Note that cloning a package installation with dpkg --set-selections doesn’t restore the automatic/manual mark in APT. See Restoring all data and dependencies from dpkg –set-selections ‘*’ for more details. You can save the marks on the source system with

apt-mark showauto >auto.list

and restore them on the target system with

xargs apt-mark auto <auto.list

Since computers are connected to each other, services are growing fast. Email, Social Media, Online Shop, Chat until Web Conferencing are services that used by user. But on the other side this connectivity just likes a double-side knife. It’s also possible to send bad messages to those computers like Virus, malware, trojan-apps are one of them.

$ sudo dpkg --get-selections | grep ufw
ufw 		install

$ sudo apt-get install ufw

$ sudo ufw status

$ sudo ufw enable

Firewall is active and enabled on system startup

$ sudo ufw disable

$ sudo ufw status verbose

Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing)
New profiles: skip
$

L’organisation de votre répertoire personnel ou même de votre système peut être particulièrement difficile si vous avez l’habitude de télécharger toutes sortes de choses sur Internet.

Souvent, vous constaterez que vous avez téléchargé le même mp3, pdf, epub (et toutes sortes d’autres extensions de fichiers) et que vous l’avez copié dans différents répertoires. Cela peut encombrer vos répertoires de toutes sortes de choses dupliquées inutiles.

Dans ce didacticiel, vous allez apprendre à rechercher et à supprimer des fichiers en double sous Linux à l’aide des outils de ligne de commande rdfind et fdupes, ainsi qu’à l’aide d’outils d’interface graphique appelés DupeGuru et FSlint.

Une note de prudence – faites toujours attention à ce que vous supprimez sur votre système car cela peut entraîner une perte de données indésirable. Si vous utilisez un nouvel outil, essayez-le d’abord dans un répertoire de test où la suppression de fichiers ne posera pas de problème.

Rdfind – Trouve les fichiers en double sous Linux

Rdfind provient de la recherche de données redondantes. C’est un outil gratuit utilisé pour trouver des fichiers en double dans ou dans plusieurs répertoires. Il utilise la somme de contrôle et trouve les doublons basés sur le fichier contient non seulement des noms. Lire la suite…

Introduction

For an introduction to firewalls, please see Firewall.

UFW – Uncomplicated Firewall

The default firewall configuration tool for Ubuntu is ufw. Developed to easeiptables firewall configuration, ufw provides a user friendly way to create an IPv4 or IPv6 host-based firewall. By default UFW is disabled.

Gufw is a GUI that is available as a frontend.

Basic Syntax and Examples

Default rules are fine for the average home user

When you turn UFW on, it uses a default set of rules (profile) that should be fine for the average home user. That’s at least the goal of the Ubuntu developers. In short, all ‘incoming’ is being denied, with some exceptions to make things easier for home users.

Enable and Disable

Enable UFW

To turn UFW on with the default set of rules:

sudo ufw enable

To check the status of UFW:

sudo ufw status verbose

The output should be like this:

youruser@yourcomputer:~$ sudo ufw status verbose
[sudo] password for youruser:
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing)
New profiles: skip
youruser@yourcomputer:~$

Note that by default, deny is being applied to incoming. There are exceptions, which can be found in the output of this command:

sudo ufw show raw

You can also read the rules files in /etc/ufw (the files whose names end with .rules).

Disable UFW

To disable ufw use:

sudo ufw disable

Lire la suite…