Monday, 16 November 2015

UGC-NET Computer Science UNIX Questions with Explanation

In this Blog we are providing all the UGC-NET Computer Science previous year Questions with explanation:

Q : 1 Which of the following is incorrect related to UNIX?
(A) "$ chmod +r emp1" and "$ chmod a+r emp1" are equivalent
(B) "$ chmod +x emp1" and "$ chmod a+x emp1" are equivalent
(C) "$ chmod +w emp1" and "$ chmod a+w emp1" are equivalent
(D) None of the above

Answer: (C)

chmod: Changing File Permissions
The default security feature provided by UNIX write protects a file from all except the owner of the file. Generally, all users have read access by default, but it could be different on each system. We can change the default permissions by umask command. 

Structure of chmod command contains three components:
1. Category of user (owner, group or others)
2. Operation to be performed (assign or remove a permission)
3. Permission type (read, write, execute)





Abbreviations used by chmod:


chmod Usage
Hence option (C) is incorrect.

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