JNTU B.Tech Semester Examinations, UNIX PROGRAMMING, Aug/Sep 2008

JNTU III B.Tech Semester Supplimentary Examinations, Aug/Sep 2008


( Common to Computer Science & Engineering and Information Technology)


1. “Operating systems like UNIX provide services both for programs and users”. Justify this statement with suitable examples.


2. What is a filter in UNIX? Explain any four filters in detail with examples.


3. (a) If x has the value 5, and you reassign it with x=”expr $x+10”, what is the

new value of x? What would have been the value if single quotes were used?

What’s wrong with all this anyway?

(b) Devise a script that accept 2 directory names bar1 and bar2, and deletes those

files in bar2 whose contents are identical to their namespaces in bar1.


4. (a) Write a shell script which gets executed the moment the user logs in. It should

display the message “good morning/good afternoon/good evening” depending upon the time at which the user logs in.

(b) Explain about here documents with an example.


5. Write syntax of following system calls.

(a) chmod

(b) chown

(c) unlink

(d) link.


6. Write the system calls for process termination in detail.


7. Write in detail about locking regions.


8. Explain the following concepts

(a) Pipes in single process

(b) Pipes in single process, immediately after fork

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