IV/BCA/403 Student's Copy
2 0 1 8
4th Semester
BACHELOR OF COMPUTER APPLICATIONS
Paper BCA-403
UNIX and Shell Programming
Old Course
Full Marks 75
Time 3 hours
PART A—OBJECTIVE
Marks 25
The figures in the margin indicate full marks for the questions
SECTION—A
Marks 15
1. Tick the correct answer in the brackets provided 1×10=10
After you have entered text in your file, to save and quit editing mode
you will use
Shift ZZ Esc Shift YY
Esc :wq Exit
The directory containing all device files is
/etc /temp
/dev /usr/bin
If the file needs to be executed only by the user, the expression
required is
chmod u+x chmod a+x
chmod h+r chmod i+j
/561 1 Contd.
The command performs
comparing two files
compressing file
copying file
communication
The df command reports
amount of free space available
the difference of two files
defragmentation
current time
The exit command with a value 0 is used when
something went wrong
everything went fine
debugging
in execution
The output redirection operator is


Which command is used to remove a file?
remove rm
mv del
To count the line, word and character in a file, we use
wc lwc
count wlc
The command which is used for text-based calculator is
bc calc
cb xcalc
IV/BCA/403 2 Contd.
2. State whether the following statements are True or False by putting a
Tick mark in the brackets provided 1×5=5
Head is the command used to display the top of the file.
True False
The while loop gets executed so long as the exit status of the test
command is 1.
True False
The command ps is used to display the characteristics of UNIX.
True False
The /dev/null does not add any space in the hard disk.
True False
The kernel interacts with the machine's hardware and the shell with
the user.
True False
SECTION—B
Marks 10
Answer the following questions 2×5=10
1. What are internal and external commands? Give one example each.
2. What is the purpose of system calls?
3. What do you mean by access permission?
4. What is the function of eval?
5. What are the privileges of superuser?
IV/BCA/403 3 Contd.
PART B—DESCRIPTIVE
Marks 50
The figures in the margin indicate full marks for the questions
1. Explain the parent-child relationship with a suitable diagram. 4
Explain the following commands with example 6
cp echo who
OR
Describe the architecture of UNIX system with a suitable diagram. 10
2. Explain each column of the output of ls-l command. 10
OR
Briefly explain the three modes of vi editor. 10
3. Describe the mechanism of process creation. 10
OR
What are the activities performed by the shell in its interpretive cycle? 6
Write a short note on /dev/tty and pipe.
4. Briefly explain the following filters 2×5=10
Pr head
tail sort
tr
OR
Mention the usage of any four options of grep command with example. 10
5. What are the three types of UNIX file system? 10
OR
How do you handle a signal with trap in shell programming? 4
How does while and for loop function in shell programming?