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(COMP111)[2009](f)midterm~ph_csl^_10136.pdf
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THE HONG KONG UNIVERSITY OF SCIENCE & TECHNOLOGY

COMP111: Unix and Script Programming

Midterm Exam
Fall 2009
Friday 6 Nov 2009, 10:00-11:50



Student Name: ___________key_________________________________

Student ID: _________________________________________________

Lab Section: ________________________________________________


Instructions:

This is a closed-book, closed-notes examination.
Write your name, student ID, and lab section on this page.
Answer all questions in the space provided.


For Grading Purposes Only:

Problem 1 _______________/10
Problem 2 _______________/4
Problem 3 _______________/5
Problem 4 _______________/9
Problem 5 _______________/4
Problem 6 _______________/4
Problem 7 _______________/4
Problem 8 _______________/8
Problem 9 _______________/6
Problem 10 ______________/3
Problem 11 ______________/6
Problem 12 ______________/8
Problem 13 ______________/10
Problem 14 ______________/4
Problem 15 ______________/3
Problem 16 ______________/12

Total: ______________/ 100

1. Unix Utilities and File System [10 marks]
Write a one-line command for the following tasks:

a) Remove the empty directory tmp.
rmdir tmp OR rm CR tmp


b) Allow the user to execute the directory cgi-bin, but disallow everyone to write to it. Note that we do not know the original permission of cgi-bin.
chmod u+x ,a-w cgi-bin (numerical not accepted) OR
chmod u+x cgi-bin; chmod a-w cgi-bin


c) Display the contents in the file dictionary.txt in lexical order.
sort dictionary.txt


d) Display the last 30 lines in the file longtext.txt.
tail -30 longtext.txt OR tail Cn30 longtext.txt
popup_menu"OK"

e) Append the date into the end of the file date.txt.
date >> date.txt


f) List the files and directories in long format for the directory inside your home directory. (You do not know your username however.)
ls Cl ~ OR ls Cl $HOME


g) Display the contents of the file textfile.txt with duplicate adjacent lines removed, and with line numbers.
uniq textfile.txt | cat -n


h) Display only lines which contain your own username to the screen showing who is logged on, where and when.
w | grep `whoami`
who | grep `whoami`
finger | grep `whoami`
w | grep $USER

2. Links [4 marks]
a) What is the result shown on the screen after the following sequence of commands is executed?
echo "testing" > testing.txt ; ln testing.txt\ TESTING; ln TESTING testing; rm TESTING ; rm Cf\ testing.txt ; cat testing

testing is shown on screen (1 mark)


b) What is the result shown on the screen after the following sequence of commands is executed?
echo "testing" > testing.txt ; ln Cs testing.txt\ TESTING; ln TESTING testing; rm TESTING ; rm Cf\ testing.txt ; cat testing

testing is not found (1 mark)


c) What is the result shown on the screen after the followi