Setting up Ubuntu

Customizing the launcher

Removing icons

The Lanucher is the vertical stack of application icons at the left end of the window. Clicking on an icon starts the corresponding application. To remove unnecessary applications from the Lanucher, right-click on the icons and choose Unlock from Launcher. Unix users normally start their application from a terminal window, so you probably want to have few icons in the Launcher.

Adding a terminal application

You will need a terminal window to issue Unix commands. A recommended terminal applications is gnome-terminal. Click on the uppermost icon in the Launcher, called Dash Home. Install the Gnome terminal application by writing its name in the Application text field. Then right-clicking on the corresponding new icon in the Launcher and choose Lock to Launcher. Now you have an icon from the Gnome terminal.

You can create tabs in the Gone terminal by clicking on that window and type Ctrl-shift-t for each tab you want.

Customizing the keyboard

Programmers frequently need curly braces and brackets. An American/English keyboard has these key in convenient places to the right on the keyboard. If your keyboard is not American/English, you can easily add a vritual American/English keybord. Click on the System Settings icon in the Lanucher, then Keyboard Layout, then Options..., then Key(s) to change layout, choose Right Ctrl + Right Shift. In the Keyboard Layout window, click on English (US) keyboard, then on the + button, find an the keyboard that corresponds to your physical keyboard (e.g., Norwegian (Macintosh, eliminate dead keys). Thereafter, you can switch between an English/American keyboard and the physical keyboard using Ctrl (on the left) and the right shift key. The keyboard in action can be viewed to the right in the panel at the top of the Ubuntu window.

The Control key is heavily used in Unix systems, and many prefer to have the Control key on the Caps Lock key. You can do this in the host system. Alternatively, you can set this in Ubuntu: click on the System Settings icon in the Launcher, click Keyboard Layout, then Options..., click Ctrl key position, click Caps Lock as Ctrl.

Convenient shortcuts

• Make Ctrl-3 switch between windows: click the System Settings icon, then Keyboard, choose the Shortcuts tab, then Navigation, scroll down to Switch application, choose it and watch the key name change to New accelerator. Now you can type the key combination you want for changing applications, say Ctrl-3.
• Customize the Gnome terminal such that Ctrl-1 and Ctrl-2 moves to the next or previous tab, respectively. Launch gconf-editor, choose apps, gnome-terminal, keybindings, next_tab, right click and choose Edit key.... Fill in <Control>2. Choose prev_tab, right click, choose Edit key... and fill in <Control>1.

Installing packages

Text editor

Install an excellent text editor, either emacs or vim (gedit comes with standard Ubuntu):

Terminal> apt-get install emacs
Terminal> apt-get install vim

Web browser

Ubuntu comes with the Firefox web browser, but occasionally it does not launch correctly. An alternative is Gnome's Epiphany browser:

Terminal> apt-get install epiphany-browser

If you prefer the Chrome browser, launch firefox or epiphany-browser, download Chrome as a .deb file (downloaded files go by default to the Downloads directory). Then run

Terminal> cd Downloads
Terminal> sudo apt-get install libgconf2-4 libnss3-1d
Terminal> sudo dpkg -i google-chrome-stable_current_amd64.deb

Useful software

Some installation scripts (actually used to build Vagrant virtual machines) can be used to conveniently install basic packages for a scientific computing environment in a Linux machine:

• A minimal installation
• A more comprehensive installation
• A rich installation

Terminal> bash install_rich.sh

Here is a brief explanation of some of the most important packages in a Linux installation.

Ultra-quick intro to Unix (sufficient for programming)

Unix commands are written in a terminal window, also called console window, xterm, rxvt, konsole, or shell.

Below is a sample session illustrating all the commands above. We

1. create a new folder named mydir
2. move to the new folder
3. start the emacs editor and write a program file myprog.py
4. copy myprog.py to myprog.py-copy
5. rename myprog.py to prog1.py
6. list the files in the current folder
7. delete myprog.py-orig
8. list the files in the current folder
9. move back to the parent folder
10. rename the mydir folder to the new name trash
11. list files in this folder and redirect output of ls to a file
12. look at the file with less
13. delete the trash folder
14. log on to another machine, newer.ifi.uio.no, under the name smartie

Unix> mkdir mydir
Unix> cd mydir
Unix> emacs myprog.py &
Unix> cp myprog.py myprog.py-orig
Unix> mv myprog.py prog1.py
Unix> ls
myprog.py     myprog.py-orig
Unix> rm myprog.py-orig
Unix> ls
prog1.py
Unix> cd ..   # .. is the quick name of the parent folder
Unix> mv mydir trash
Unix> ls > out
Unix> less out   # press q to quit less
4 -rw-r--r-- 1 hpl hpl 6 2008-08-21 07:33 trash
out (END)
Unix> rm -r trash    # need the -r to remove a folder
Unix> ssh -X smartie@newer.ifi.uio.no
password:

Everything after # is a comment in Unix. Note that cd .. is a quick way of moving one folder up in the folder hierarchy.

Here are some more Unix goodies:

• The TAB key can be used to complete filenames: just type the first character of a filename and press TAB to expand the name.
• The asterisk character (*) can be used as a symbol for "any sequence of characters" in filenames. For example, if you want to list all your Python programs in a folder, you can write ls *.py. With the asterisk you can quickly specify a set of files.
• Packing a set of files together as one compressed file is a useful feature when you want to send the set of files in email. The Unix tar command is used to pack and unpack file collections (like zip or WinZip on Windows). Suppose you want to pack together all your Python programs in one compressed file called myprograms.tar.gz. Packing and unpacking is done by

Unix> tar cvzf myprograms.tar.gz *.py   # pack
Unix> tar xvzf myprograms.tar.gz        # unpack