lsb_release -a: display Ubuntu version
df: état du disque
free: état de la mémoire
ps: monitor les process
rm: delete a file
mkdir: to create a directory, rmdir: to delete a directory
ln -s: to create a link, rm -r: to remove a slink
cat: to print content like cat /proc/meminfo, cat /proc/cpuinfo

sudo -s user to become a user, user empty to become root

rpcinfo: makes an RPC call to an RPC server and reports what it finds.
rpcinfo -p [host]
lsb_release -a to display linux version

foremost: Recover files using their headers, footers, and data structures
sudo foremost [-h][-V][-d][-vqwQT][-b<blocksize>][-o<dir>][-t<type>][-s<num>][-i<file>]

Ubuntu

Network:
netstat: état du réseau
sudo nano /etc/network/interfaces
auto eth0
iface eth0 inet static
        address 192.168.10.2
        netmask 255.255.255.0
        gateway 192.168.10.1
        dns-nameservers 8.8.8.8 8.8.4.4
sudo /etc/init.d/networking restart
sudo service networking {restart/stop/start}

Rename server name:
sudo nano /etc/hostname
sudo nano /etc/hosts

Packets:
Télécharger des packages du web: wget urlInstaller des packages en mode ligne: apt-get install package
Enlever des packages en mode ligne: apt-get remove package
List des packages installés: dpkg --get-selections | grep package
Mettre à jour la liste des fichiers disponibles: sudo apt-get update
Mettre à jour tous les paquets installés sur le système: sudo apt-get upgrade
Mettre à jour tous les paquets installés vers les dernières versions en installant de nouveaux paquets si nécessaire: sudo apt-get dist-upgrade
Mettre à jour la version installée: sudo do-release-upgrade, -d to beta version

Server:
Arrêter le serveur: shutdown -h now
Rebooter le serveur: shutdown -r now
Configurer le réseau: sudo nano /etc/network/interfaces
Relancer le réseau: sudo /etc/init.d/networking restart
Afficher les utilisateurs: who ou ps -ef|grep tty
Editeur avacancé: nano filename, afficher un fichier cat filename


The login screen uses a different configuration script to the main part. To change the keyboard layout it uses you have to edit the configuration file. (I had the same issue changing to dvorak).
To get the gdm login screen to recognise the your layout:
sudo gedit or nano /etc/default/console-setup
gksudo gedit  /etc/X11/xorg.conf

List of running process
ps aux | grep -i process_name

firewall https://help.ubuntu.com/community/IptablesHowTo http://ubuntuforums.org/showthread.php?t=159661

display tables: sudo iptables -L
erase tables: sudo iptables -F
save rules: sudo iptables-save > /etc/iptables.rules

FTP allow
sudo iptables -A INPUT -i eth0 -p tcp -m tcp --sport 21 -m state --state ESTABLISHED -j ACCEPT 
sudo iptables -A INPUT -i eth0 -p tcp -m tcp --sport 20 -m state --state ESTABLISHED,RELATED -j ACCEPT 
sudo iptables -A INPUT -i eth0 -p tcp -m tcp --sport 1024:65535 --dport 1024:65535 -m state --state ESTABLISHED -j ACCEPT 
sudo iptables -A OUTPUT -o eth0 -p tcp -m tcp --dport 21 -m state --state NEW,ESTABLISHED -j ACCEPT 
sudo iptables -A OUTPUT -o eth0 -p tcp -m tcp --dport 20 -m state --state ESTABLISHED -j ACCEPT 
sudo iptables -A OUTPUT -o eth0 -p tcp -m tcp --sport 1024:65535 --dport 1024:65535 -m state --state ESTABLISHED,RELATED -j ACCEPT

Support NTFS
sudo aptitude install ntfs-3g ntfsprogs ntfstools

Partitionner les disques
apt-get install gparted

Mozilla Thunderbird
Personnal folder is $home/.thunderbird/xxxxxxxx.default/

Open SSH
sudo apt-get install openssh-server
sudo service ssh {restart/stop/start}