released: 04/13, 10:30
due: 04/19, 23:59

Answer the following questions.
Submit your answers to Canvas assignments.
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1. Linux dir permissions (8 points)

In Linux, each file/dir has its access control list (ACL).
That's what we know as "permissions".

To check permissions:
  - one can use "ls -l file" to see a file's permissions
  - one can use "ls -ld dir" to see a dir's permissions

To change permissions:
  - set "r--------" by "chmode 0400 dir" (4 in oct-num means '100')
  - set "-w-------" by "chmode 0200 dir" (2 in oct-num means '010')
  - set "--x------" by "chmode 0100 dir" (1 in oct-num means '001')

Now, run the following cmds and answer questions below.

  $ mkdir /tmp/dir1
  $ touch /tmp/dir1/file1
  $ touch /tmp/dir1/file2
  $ mkdir /tmp/dir1/dir2

1.a (2 points) understanding 'r'
    Run the following cmds:

     $ chmod 0400 /tmp/dir1
     $ ls /tmp/dir1

    What do you see?
    Write down the output and explain why in 1--2 sentences.



1.b (2 points) understanding 'w'
    Run the following cmds:

     $ chmod 0200 /tmp/dir1
     $ touch /tmp/dir1/file3

    What do you see?
    Write down the output and explain why in 1--2 sentences.



1.c (2 points) understanding 'x' I
    Run the following cmds:

     $ chmod 0100 /tmp/dir1
     $ ls /tmp/dir1

    What do you see?
    Write down the output and explain why in 1--2 sentences.


1.d (2 points) understanding 'x' II
    Now, run the following cmds:

     $ chmod 0100 /tmp/dir1
     $ touch /tmp/dir1/dir2/file4
     $ ls /tmp/dir1/dir2/

    What do you see?
    Write down the output and explain why in 1--2 sentences.



2. Feedback (2 points)

This is to gather feedback. Any answer, except a blank one, will get points.


2.a  Please state the topic or topics in this class that have been least clear to you.


2.b  Please state the topic or topics in this class that have been most clear to you.


3.c (optional) anything you'd like us to know?