1

What is the UNIX “who” command used for?

1. To list the users authorized to use this computer
2. to get more detailed information on users (like the finger command)
3. to list the users currently logged on to the system
4. to list a detailed information on the user who has sent you the mail you just received

2

What does the following UNIX cp command do?

1. copies all the files from /usr/local/bin to the directory /usr/local/bin/w
2. copies some of the files from /usr/local/bin to the directory /usr/local/bin/w
3. Wouldn’t do anything because the command “copy” should be used instead of “cp”.

1. Wouldn’t do anything because there are not sufficient number of arguments (parameters).

3

Suppose you have logged on to host “gunes” as user “cayfer” and you have the following files (listed by the “ls –l” command) in your home directory:

4

Suppose you have logged on to host “gunes” as user “cayfer” and you have the following files (listed by the “ls –l” command) in your home directory:

5

Suppose you have written a C program and entered its source to a file called “myprog.pl”. To run this program; (Please indicate CLEARLY which of the following stements are TRUE and which of them are FALSE.)

6

7

What does the the “cat *.txt | less” command do?

1. Catalogues all files with extension “txt” to a file called “less”
2. Converts all files with extension “txt” to programs
3. displays a detailed file name listing (with access flags, creation date, size etc) of files with extension “txt” and places the result in a file called “less”.
4. displays the contents of files with extension “txt” and places the result in a file called “less”.

8

Suppose you have logged on to host “gunes” as user “cayfer” and you have the following files (listed by the “ls –l” command) in your home directory:

1. rm –all files
2. rm –a files directories
3. rm –l *
4. rm –r *.*
5. rm –r * (although there is a ownership problem, this is the command to use)

9

Suppose you have a text file (“ctp203_list_of_students.txt”) which contains a list of 3450 students registered to CTP-203 course. A few example lines out of this file looking like :

Name        Surname   Grade
=========== ========= =====

Ugur        Ayfer     gr:A+
Ali         Veli      gr:B-
Hasan       Huseyin   gr:C
Ayse        Fatma     gr:C
etc.        etc.

Which UNIX command would you use to display students who got an A+ in this course

1. sort A+ | more ctp203_list_of_students

10

# Program starts here.
# Count the number of arguments
if ( $#ARGV != 2 ) { 1
print "Incorrect number of arguments!\N": 2
exit;
}

# get the first and second arguments
file1 = @ARGV[0]; 3, 4
file2 = @ARGV[1]; 5, 6
# check whether they exist

if ( ( -d $file1) && ( -f $file2)) { 7
print FILE1 FILE2 "Error! $file1 does not exist or $file2 exists!\n"; 8
system;
}

open (INFILE, $file1);
open (OUTFILE, $file2); 9

while (<INFILE>) {
$line = <STDIN>; 10
print OUTFILE $_;
}