A Very Short Introduction to Linux
Kyrre Ness Sjøbæk
University of Oslo, FYS3150
10th of September, 2009
This talk, and related files, may be found at
http://folk.uio.no/kyrrens -> Nyheter -> Linuxkurs
There is a short compendium about the terminal!
Intended Audience:
People who have never really
used Linux before
People who have a little experience
with Linux, and want to work efficiently
Outline
General stuff
How to setup and use the file explorer
Tips and tricks with the graphical environment
Some Firefox tricks
The Terminal at a glance
Basic commands
TAB completion
Emacs – it isn't dangerous
Important keybindings
Tips & tricks
General stuff – Use of the file
manager “Nautilus” (I)
Default behavior:
Open a new folder = Open a new window
To change it: Open a folder, hit
edit -> preferences -> behavior -> Always open in browser window
Previews of pictures etc. may be turned on in the same
dialog
General stuff – Use of the file
manager “Nautilus” (II)
Sometimes you want to change the default
program used to open a file type
You may choose
Example 1: Mostly you just want to view an image, but
sometimes you want to edit (Gimp)
Example 2: .eps files have a really bad default program
to open it. Set it to “Document viewer” (evince)
Right-click a file of the interesting type
You may here choose another program only once
Click “preferences -> Open with” to change default
General stuff – Tips and tricks with
the graphical environment (I)
You have “multiple
desktops”
These act as extra screens
Use the mouse on the
onscreen control, or
keyboard shortcuts
Tips:
Use one desktop for code,
one for a terminal, one or
two for report writing, one
for web...
Keyboard shortcuts:
Move around (change active desktop):
Control-alt-<arrow>
Move around, and drag a window with you:
control-alt-shift-<arrow>
General stuff – Tips and tricks with
the graphical environment (II)
Very useful: Know how hard
your computer is working
To get it:
Right click top or bottom panel,
“Add to panel”
Choose “System Monitor”
Right-click the thing that pops
up -> properties -> check at
least “CPU” and “Memory”
Harddrive activity
Network activity
Memory: Dark green means
“in use by a program”.
Ligth green means that its
used to get files faster.
Watch the dark green!
CPU: Blue means “in use”.
Note: On a dual core, 50% means
that one core is working max,
other is sleeping. (similarly for quad)
A few tips & tricks with Firefox
Useful keyboard shortcuts:
Control-L
: Activate address bar
Control-K
: Activate search bar
Control-T
: Make new tab, activate address bar
Control-click or mousewheel-click
: Open link in new tab
Control-F
: Search in page
Making a “quicksearch”:
Right-click on a search field, select “Make keyword for this search”. Pick a
name and a keyword
Examples: Wikipedia as “wp”, UiO person-search as “uiop” ...
To use: type “<keyword> <searchterm>” in the address bar
The terminal at a glance
In the terminal: Use “commands” to make things
happen
A command is a special word (technically: the
name of the program which does it) followed by
a set of “arguments” – for example:
mv -R oldplace newplace
Note that commands are case sensitive:
UPPERCASE ≠ lowercase
The terminal at a glance –
Important commands (I)
Moving around in directories
:
Listing directory content
cd <newdir>
:
Change working directory
pwd
:
Print name of current working directory
mkdir <newdir>
:
Making a new directory
ls
(-la)
Copying and moving files
cp (-r) <file> <copy>
:
Copying a file
mv <file> <newname>
:
Moving / renaming a file
The terminal at a glance –
Important commands (II)
Creating and deleting files, looking inside them:
cat <filename>
:
Print the content of a textfile in the terminal
touch <filename>
:
Create a new, empty file
rm (-rf) <filename> :
Delete file or directory
Controlling programs
Control-C
:
Stopping the active program, aborting input
Control-X
:
Pausing the active program
bg
:
Unpause the active program,
and put it in the background
<command> &
:
Start a program/command,
and put it in the background
The terminal at a glance –
Important commands (III)
What programs are running, and how to stop
them:
top
:
Display a list of what programs are
active and consuming
resources (“q” to quit)
ps aux
:
Display a list of all running programs
ps aux | grep <name>
:
As above, but only display lines
containing <name>
killall (-9) <name>
:
Kill the program named <name>
kill (-9) <PID>
:
Kill the program with process ID <PID>
xkill
:
Gives you a crosshair to kill programs...
The terminal at a glance –
TAB completion
Avoid writing long command- and file names:
Use the “TAB” key
To do it: Start writing a command/filename, and
when you have entered the first 2-3 letters, try
hitting “TAB”.
If it is unambiguous (no other
command/filename starting with the same
letters), the terminal will fill in the rest. If it is
ambigious, try 1-2 more letters, and hit tab
Hitting tab twice (when there are ambiguities)
brings up a list of possibilities.
The terminal at a glance –
screen (I)
If you have a long job, you can start it within a
“screen”
This gives you a new “terminal”, independent of
the physical display/keyboard in front of you.
You can “detach” and later “reattach” to this
terminal.
You may, for example, start a long job in screen,
detach and log of the computer, go home, eat
dinner/whatever, and later ssh the computer,
reattaching to check progress etc.
The terminal at a glance –
screen (II)
Important commands:
screen
: Starting a new screen
control-A-D : Detach from a screen
screen -r
: Reattach to a running screen
Emacs – it isn't dangerous
One of the best editors for pure text – especially
programming (“kate” is also good)
In development since the 70's (1984: GNU emacs)
Has an enormous amount of features, scriptable (LISP)
Can do syntax highlighting for almost any language
While emacs has a steep learning curve –
it is worth it
To start emacs:
emacs <filename>
Emacs – Important concepts
Important concept in emacs:
Buffer
– A piece of text (an open file, a dialog, a
command line etc.)
Window
– Where the buffers are displayed
Most commands in emacs is made with holding
control (C) or alt (Meta) while typing something
“Space cadet” keyboard:
Seven (7!) modifiers,
used as “chords” with
the left hand.
Modern PC keyboards: 5
Control, Alt, Shift,
AltGr, Super (windows-key).
Some laptops also have
an extra “Fn” key.
Worse placement of modifiers on PC
Emacs – Important keybindings (I)
Saving files, closing emacs, etc.
C-x-s : Save current buffer
C-x-c : Close emacs
C-x-f : Find (open) file
C-_
: Undo (to type “_” (underscore): Shift+”-”)
Searching in the text:
C-s
: Search in current buffer
M-%
: Search and replace in current buffer
Emacs – Important keybindings (II)
Marking, copy & paste:
M-w
:
Copy marked area
C-w
:
Cut marked area
C-y
:
Paste
C-space
:
Set mark
Meta-x: the “command line” inside emacs.
Press “M-x” and type the command.
Watch the bottom area (minibuffer).
TAB-completion is supported.
M-x recover-this-file
:
Read autosave information
(“#filename#” file)
(useful if something crashed...)
M-x comment-region
:
Make the marked area a comment
Emacs – Important keybindings (III)
Making room for more buffers:
C-x 2 : Divide current window horizontally
C-x 3 : Divide current window vertically
C-x 1 : Only show current window
C-x o : Switch active window
C-x b : Switch which buffer is showing in the current
window
C-x k : Close (kill) current buffer
Note: Hit first C-x and then hit 1,2,3,o,b, or k !
Emacs – hints about the GUI
Name of the buffer
showed in the window
Character map:
“-1” = Latin1 (ISO-blahblah)
“-u” = UF8
Two stars “**”:
Unsaved file
Which line is
the marker on?
Minibuffer – Emacs writes status messages,
asks for input etc. here. Watch it!
Currently using “Text” edit mode
(for syntax highlighting etc.) may also be C++, LaTeX, ...)
Questions?