Trinity McCurdy

HW2 

What are the fundamental particles and forces? How many particles standard model of particle physics has?

! The Standard Model of Particle Physics consists of 17 particles, including: mass particles (quarks; leptons), force carrying particles (i.e. electrons; neutrinos), and the Higgs Boson.

! 4 Fundamental Forces: Electromagnetic Force, Weak Force, Strong Force, and Gravitational Force (Not included in the Standard Model). There are 12 fundamental Particles...6 quarks: Up, Down, Charm, Strange, Top, Bottom/Beauty; and 6 leptons: Electron, Electron Neutrino, Muon, Muon Neutrino, Tau, and Tau Neutrino.

What is spin of a fundamental particle? 

!! The Spin of a fundamental particle is their "intrinsic angular momentum." Spin is used to classify particles by determining the nature of its individual energy distribution within a collection of particles. 

What is the difference between bosons and fermions?

! Bosons are particles that have integer spin, while Fermions are particles that have half-integer spin. 

! Fermions are confined by the Pauli exclusion principle, meaning 2 fermions can't occupy the same state. Bosons aren't confined because of their integer spin. Instead, they distribute energy in a way described as Bose-Einstein condensation; At low temperatures, an unlimited number of Bosons can occupy the same state.

! The wavefunction describing a collection of bosons must be symmetric to the exchange of identical particles, whereas fermions require asymmetry. 

What is Linux?

! Linux is a free computer operating system that utilizes a command prompt instead of a familiar graphical interface. It also offers the means on how to communicate with your computer more effectively.

What is a Linux Shell?

! A Linux Shell describes the variant of Linux you are working in- bash or tcsh.

How do you find which shell your are working in?

echo $SHELL

What is basic linux command structure?

command -option1 -option2 -option3...  target1 target2

• What did it seem like the 'touch' command does?

The touch command seems to create a script within a directory.

• Why do you think we include that '.' after the 'find' commands?

'.' is to specify that the script is to be created within the current directory.

• • Based on the outputs from the four 'find' commands, what purpose do you think the '*' character serves? (Hint: it's called the "wildcard" character in linux jargon)

The '*' is a substitution for the unknown value. It searches through every script.

• • What did the 'rm' command do, and how do you think 'rm' differs from the 'rmdir' command we saw earlier? Warning: There is no way to undo the 'rm' command!

'rm' deletes whatever the target is. It differs from 'rmdir' in that 'rmdir' deletes the entire directory.

• Finally, to test your understanding, why do you think that you should never run the command 'rm *'? True story: a thoughtless 'rm *' almost deleted all of Toy Story 2! (https://www.youtube.com/watch?v=8dhp_20j0Ys)

I think running 'rm *' would wipe out everything. And because there is no specified directory, I'd assume it would delete everything even outside of '.'.

• Try the following commands and answer the questions below.

echo "test"

echo "test1" > log.txt

ls

cat log.txt

echo "test2" > log.txt

cat log.txt

echo "test3" >> log.txt

cat log.txt

• What do the '>' and '>>' operators do? How are they similar? How are they different?

> creates a file for a specific command. >> adds another command to the file. The only difference between them is that >> adds a command without replacing the previous one.

• What is one potential danger of using the '>' operator?

If I were to use this operator without remembering that I had assigned another command to the same file, I could ruin any scripts using that file.

• What do you expect to see if you run:

ls -l > log.txt

cat log.txt

I expect this would cause log.txt to list all the changes made to the directory. But, since > replaces the "test"s there won't be anything to list.

• Use google and collect 10 Linux commands that you think could be useful for you. For example, one such command would be to find and replace a word or phrase in a large text file. 

  • Show that your commands actually work

df -h

diff

[tmccurd2@hepcms-in2 ~/funkhouse] $ diff -b Moody.txt Forever.txt

1,4cl,4

<blue

<cold night

<lemon tea

<Streetlight

---

>Blue

>cold

>melted

>Nighty night

grep

ps and -less

mv

(Changing directory name)

[tmccurd2@hepcms-in2 ~]$ ls

a . out   MONHu     new_directory TEST             testscript.tcsh~

main.cpp  mycode.C  rootlogon.C   testscript.tcsh  test.txt

[tmccurd2@hepcms-in2 ~]$ mv new_directory/ funkhouse

[tmccurd2@hepcms-in2 ~]$ ls

a.out      main.cpp mycode.C     TEST            testscript.tcsh~

funkhouse  MONHu    rootlogon.C  testscript.tcsh  test.txt

[tmccurd2@hepcms-in2 ~]$ mv TEST/

mv: missing destination file operand after 'TEST/'

Try 'mv --help' for more information.

[tmccurd2@hepcms-in2 ~]$ mv TEST/ Villa

[tmccurd2@hepcms-in2 ~]$ ls

a.out     main.cpp  mycode.C   testscript.tcsh  test.txt

funkhouse MONHu    rootlogon.C testscript.tcsh~  Villa

(Moving files to different directory)

sort and comm

exit