sudo command – run command as root

sudo -s – open a root shell

sudo -s -u user – open a shell as user

sudo -k – forget sudo passwords

gksudo command – visual sudo dialog (GNOME)

kdesudo command – visual sudo dialog (KDE)

sudo visudo – edit /etc/sudoers

gksudo nautilus – root file manager (GNOME)

kdesudo konqueror – root file manager (KDE)

passwd – change your password Display

sudo /etc/init.d/gdm restart – restart X and return to login (GNOME)

sudo /etc/init.d/kdm restart – restart X and return to login (KDE)

(file) /etc/X11/xorg.conf – display configuration

sudo dexconf – reset xorg.conf configuration

Ctrl+Alt+Bksp – restart X display if frozen

Ctrl+Alt+FN – switch to tty N

Ctrl+Alt+F7 – switch back to X display System Services¹

start service – start job service (Upstart)

stop service – stop job service (Upstart)

status service – check if service is running (Upstart)

/etc/init.d/service start – start service (SysV)

/etc/init.d/service stop – stop service (SysV)

/etc/init.d/service status – check service (SysV)

/etc/init.d/service restart – restart service (SysV)

runlevel – get current runlevel Package Management¹

apt-get update – refresh available updates

apt-get upgrade – upgrade all packages

apt-get dist-upgrade – upgrade with package replacements;upgrade Ubuntu version

apt-get install pkg – install pkg

apt-get purge pkg – uninstall pkg

apt-get autoremove – remove obsolete packages

apt-get -f install – try to fix broken packages

dpkg –configure -a – try to fix broken packages

dpkg -i pkg.deb – install file pkg.deb

(file) /etc/apt/sources.list – APT repository list Network

ifconfig – show network information

iwconfig – show wireless information

sudo iwlist scan – scan for wireless networks

sudo /etc/init.d/networking restart – reset network for manual configurations

(file) /etc/network/interfaces – manual configuration

ifup interface – bring interface online

ifdown interface – disable interface Special Packages

ubuntu-desktop – standard Ubuntu environment

kubuntu-desktop – KDE desktop

xubuntu-desktop – XFCE desktop

ubuntu-minimal – core Ubuntu utilities

ubuntu-standard – standard Ubuntu utilities

ubuntu-restricted-extras – non-free, but useful

kubuntu-restricted-extras – KDE of the above

xubuntu-restricted-extras – XFCE of the above

build-essential – packages used to compile programs

linux-image-generic – latest generic kernel image

linux-headers-generic – latest build headers Firewall¹

ufw enable – turn on the firewall

ufw disable – turn off the firewall

ufw default allow – allow all connections by default

ufw default deny – drop all connections by default

ufw status – current status and rules

ufw allow port – allow traffic on port

ufw deny port – block port

ufw deny from ip – block ip address Application Names

nautilus – file manager (GNOME)

dolphin – file manager (KDE)

konqueror – web browser (KDE)

kate – text editor (KDE)

gedit – text editor (GNOME) System

Recovery – Type the phrase “REISUB” while holding down Alt and SysRq (PrintScrn) with about 1 second between each letter. Your system will reboot.

lsb_release -a – get Ubuntu version

uname -r – get kernel version

uname -a – get all kernel information

pwd     “Print working directory” – show what dir you’re in.

ls         List the contents of a dir.

ls -l      List the contents of a dir and show additional info of the files.

ls -a     List all files, including hidden files.

cd        Change directory.

cd ..     Go to the parent directory.

Examining files

Command     Action

file       Determine the type of a file.

cat       Concatenate a file.

less     View text files and paginate them if needed.

Manipulating files and directories

Command     Action

cp        Copy a file.

cp -i     Copy a file and ask before overwriting.

cp -r    Copy a directory with its contents.

mv       Move or rename a file.

mv -i   Move or rename a file and ask before overwriting.

rm       Remove a file.

rm -r    Remove a directory with its contents.

rm -i    Ask before removing a file. Good to use with the -r option.

mkdir Make a directory.

rmdir   Remove an empty directory.