This note is nothing else then a super short wrapper for The Linux Information Project web site. We will be following order below, loosely.

This class requires a running shell environment, in order to practice commands together.


Have a look linux vs unix step with more details. Learn more

An operating system is a collection of programs that manages all the other programs.

Linux (often pronounced LIH-nuhks with a short "i") is a Unix-like operating system that was designed to provide personal computer users a free or very low-cost operating system comparable to traditional and usually more expensive Unix systems. Linux has a reputation as a very efficient and fast-performing system. Linux's kernel (the central part of the operating system) was developed by Linus Torvalds at the University of Helsinki in Finland. To complete the operating system, Torvalds and other team members made use of system components developed by members of the Free Software Foundation for the GNU Project.

What is Linux in techtarget


Why use/study linux?

Solid reasons are given here. Addition/repetition to them you will need/benefit from linux during your master/life.

I have machine with windows XX, I am afraid to loose my OP/data...

Dual boot is not that complicated. Back up everything in case unexpected situations. See details here. May be not Ubuntu? Or not a dual boot, try your own search.

Important terminal commands

Following table includes some of the common shell commands. More complete list than what is covered here is also avaliable on LINFO web site.

Command Effect (Let's fill together)
ls, ls-a, ll
mkdir dirname
rm dirname
grep dirname
du dirname
tar -cvf compressed.tar.gz dirname

Do it yourself

tar -cvf iso_64_k2.tar.gz *.nc
du -h --max-depth=1 | sort -h


Can we use sheel commands in order to list size of directories under a given directory, which list is sorted biggest directory to smallest?


Small tricks you might find it handy to use in Unix-like operation systems.

Wildcards: A wildcard is a character that can be used as a substitute for any of a class of characters in a search, thereby greatly increasing the flexibility and efficiency of searches.

ls *.html *.txt
ls *.???

Pipes: Command line destinated redirection method for Linux.

Like "command_1 | command_2 [| command_3 . . . ]"

dmesg | sort -f | less
ls -al | less
ls | wc -l > count.txt

Aliases: You can defined aliases in your .bashrc to create user defined command lines abbreviations.

alias rm  = "rm -i"
alias pdw = "pwd"


If an error has been made in creating the hierarchy of directories, it is easy to remove the entire hierarchy by using the rm command with its -r option. For example, the following would delete the entire 2006 directory tree, including any files in it:

For example, the following would delete the entire 2006 directory tree(-r stands for recursively), including any files in it:

rm -r 2006

rm -r is a very powerful -- and slightly dangerous -- command, and thus it should be used with caution.

About Sudo

Great power requires great sacrifice

You've probably heard the one about "With great power comes great responsibility".

Learn more

If you haven't, you'll learn when you [su]do, from Anhad Jai Singh.


Sudo stands for either "substitute user do" or "super user do", used it with discretion.

There some command line actions requires sudo. It depends/It adjusts user privileges.


Almost every computer user might find using shell environments significantly convinied for themselves. For researchers or developers situation is more obvious.This was super short/undetailed introductory to the linux/unix environments.

Today we talk about:

  • Basic commands
  • Glance at useful links
  • Importance of self-taught