Transcript Introduction to Linux

Julien Thibault
[email protected]
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1969 - Bells Labs develop a new operating system called “UNIX”
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Beginning of the 90’s
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Linus Torvalds
PC becomes popular
UNIX too slow for these machines and not free
People switch to Windows 3.1 or MS-DOS
1991 – Linus Torvalds (University of Helsinki) starts working on the
“Linux” project
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Written in C instead of assembly code
Able to recycle code
Improved compatibility between systems
Free OS
Compliant with the original UNIX
Today – why do you care?
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De-facto OS for high-performance computing (clusters)
More and more popular in federal agencies and large companies
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Pros
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Free and open source
Large community
Secure, almost no virus (compared to Windows)
Scalable: from palm to cluster with more 100 nodes
Cons
 Not as user-friendly as Windows or Mac but getting there
 Many distributions available: Ubuntu, RedHat, Fedora, SUSE, Mandriva,
Debian…
 See: http://futurist.se/gldt/wp-content/uploads/11.04/gldt1104.png
What a Linux distribution can look like today…
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Host:
Login:
Password:
sanddunearch.chpc.utah.edu
uNID
uNID password
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Using PuTTY (Windows):
 Just enter the host name
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Using ssh (Mac or Linux):
ssh [-Y] login@host
The -Y option is used to enable GUIs (it can be slow!!)
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cd
ls [-la]
pwd
mkdir
mv
cp [-r]
change current directory
list files
show path to current directory
create new directory
move file/dir to new location
copy file (use -r for directory)
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scp [-r]
ssh
secured copy over the network
secured remote login
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man cmd
cmd command manual
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Create the directory ~/workshops/linux/test
in your home directory
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Copy the test directory to
~/workshops/linux/test2
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Move test2 to your home directory and
rename it testlinux
Try out Emacs if you cant stand VI…
http://www.cs.colostate.edu/helpdocs/emacs.html
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Insertion mode:
Command mode:
i
ESC
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dd
yy
p
u
delete current line (and copy)
copy current line
paste before cursor
undo
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/string or ?string
n or N
search string after or before cursor
go to next or previous match
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:s/pattern/string/g
replace pattern by new string
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:w
:q
:q!
Save changes
Exit
Exit and ignore any changes
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More commands at: http://www.lagmonster.org/docs/vi.html
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Create a new text document, insert “Hello world” and save it as
helloworld.txt
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Download Moby Dick from
http://www.gutenberg.org/ebooks/2701.txt.utf8 and rename it
mobydick.txt
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Delete everything that is before chapter 1
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What is the title of chapter 107?
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What is the last line?
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Move the first paragraph (chapter 1) to be after the second one
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How many times does the word ‘France’ appear in the text?
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Permissions
 Root (super user)
▪ Can control machine configuration and programs for all the user
 ls -l will display the permissions for a file/dir
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Interactive shell configuration
 aliases (e.g. “ll” instead of “ls -l”)
 environment variables
▪ $PATH: path to the executables
▪ $HOME: point to your home directory
 bash / C shell
▪ 2 different scripting methods
▪ .bashrc , .bash_profile , .profile / .tcshrc
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Inside the configuration script:
 setenv / export
 alias
Set environment variable
Create alias
C shell script example (CHPC)
alias ll “ls -l”
setenv EXEC “$HOME/programs”
setenv PATH $EXEC/bin/:$PATH
Bash script example
alias ll=“ls -l”
export EXEC=$HOME/programs
export PATH=$PATH:$EXEC/bin/
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source
echo var
apply changes to bash script for interactive shell
display value of environment variable
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which
ps [aux]
top
find
grep
cat
tail [–n]
returns the path to the command executable
list of active processes
list of top active processes (updated )
find a file or directory
find a phrase in text
display content of a file
display the last lines of a file
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su
chmod
chown
switch to superuser. Need root privileges
change permissions on a file/dir
change owner of a file/dir
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wget
download file from URL
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Find the location of the Matlab install at CHPC
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Create an environment variable called
$MATLAB_HOME that points to the install of
Matlab version R2006 and add it to your PATH so it
becomes the default version
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Create an alias to display the version of java
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Create a script called hello.sh that says “hello
world” when you run it.
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Ctrl-C
Ctrl-Z
Cancel job
Stop job
cmd &
bg
fg
jobs
execute cmd in the background
move job to background
move job to foreground
list current jobs
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$ sleep 100 — Start a dummy job in foreground. (sleep = waits a x
amount of second)
Press Ctrl+z to stop the current job.
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$ bg — Move the last stopped job to background.
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$ sleep 150 — Dummy job 1
Press Ctrl+z to stop the current job.
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$ sleep 140 — Dummy job 2
Press Ctrl+z to stop the current job.
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$ sleep 130 — Dummy job 3
Press Ctrl+z to stop the current job.
$ jobs — List all active jobs.
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$ bg 2 — Move the 2nd active job to background.