DOEACC Society 2007 Advanced Level Course In Computer Science A8-R3: BASICS OF OS, UNIX AND SHELL PROGRAMMING - Question Paper

A. left to right B. a.out C. xterm
D. trap E. set F. exec
G. 022 H. prime.out I. startx
J. nice K. ? L. filename extension
M. sleep N. wait O. signal
P. superblock Q. * R. 644
S. abbr T. inode block U. magic number
V. right to left

4.1 The _________ command is used to change the priority of running process.
4.2 If the system default permissions for an ordinary file in 666 and the umask value is 022, then permissions for the file, a, created by the command cat > a is _________.
4.3 The command cc prime.c generates _________ as the executable file.
4.4 A fully qualified domain name (FQDN) is resolved in _________ order by Domain Name Server (DNS).
4.5 The shell Meta character _________ match any string of zero or more characters in file.
4.6 The file command differentiates ranging from the different kinds of files on the basis of _________.
4.7 The list and the number of free inode blocks available in the system is stored in _________.
4.8 The system call that stops parent process and let it resume on termination of child process is _________.
4.9 Unix command to specify what to do upon receipt of a signal is _________.
4.10 To manually begin X server, use _________ on prompt.

















PART TWO
(Answer any 4 questions)

5.
a) Write an awk program, which acts like wc command, i.e., reports the number of lines, words and characters in every file passed to it as command line argument.
b) How are the pointers to the data blocks of a file stored in its inode? Show diagrammatically also.
(8+7)

6.
a) Differentiate ranging from the subsequent
i) A system call, a library function and a UNIX command.
ii) /etc/passwd and /etc/shadow
iii) User mode and kernel mode in UNIX.
(9+6)

7.
a) What will be the output of the subsequent codes? Also discuss the cause for it.
for j in a b c d e f
do
echo $ > f1
done

and
for j in a b c d e f
do
echo $j
done > f2
b) Write a shell script to learn a name and display whether that person is authorized to use the system or not. If the person is authorized, then display whether that person is currently logged in or not.
c) List the 3 standard file kinds available in UNIX. Which standard file kind is redirected when the subsequent shell metacharacter(s) is used in the commands: - <, >, >>, 2> and | (pipe)?
(5+5+5)

8.
a) What is a URL? elaborate its different components?
b) What is setuid bit? How does it work and what is its importance?

Earning:   Approval pending.