Unix Interview Questions and Answers
Question - 21 : - What do chmod, chown, chgrp commands do?
Answer - 21 : - Following are the purposes of the given UNIX commands;
chmod changes the permission set of the file.
chown changes the ownership of the file.
chgrp changes the group of the file.
Question - 22 : - Give the command for finding the current date.
Answer - 22 : - The command “date” is used to retrieve the current date.
Question - 23 : - Describe the zip/unzip command using gzip.
Answer - 23 : - The gzip command creates a zip file using given the filename in the same directory.
gunzip command unzip the file.
Question - 24 : - Can you explain the method of changing file access permission?
Answer - 24 : - There are three parts to consider when creating/changing file access permission.
File owner’s user ID
File owner’s group ID
File access mode to define
Three types of permission can define.
r – Reading permission
w – Writing permission
x – Execution permission
Question - 25 : - What are the pros of executing processes in the background?
Answer - 25 : - The main advantage is to execute processes in the background is to get the possibility to execute some other process without waiting for the previous process to get completed. The symbol “&” at the end of the process tells to the shell to execute given a command in the background.
Question - 26 : - Which UNIX command to make a new directory?
Answer - 26 : - The command mkdir directory_name is used to create a new directory.
Question - 27 : - What is the UNIX command to confirm a remote host is alive or not?
Answer - 27 : - You can use either ping or telnet to confirm a remote host is alive or not.
Question - 28 : - Differentiate between swapping and paging?
Answer - 28 : - Swapping: In this, the complete process is moved to the main memory for execution. To provide the memory requirement, process size must be less than the available main memory capacity. The implementation is easy but is an overhead to the system. Memory handling is not more flexible with swapping systems.
Paging: In this, only the required memory pages are moved to the main memory for execution. The size of the process does not a matter of execution and it no needs to be less than available memory size. Allow a number of processes to load to main memory simultaneously.
Question - 29 : - What is the ‘nohup’ in UNIX?
Answer - 29 : - To run a process in the background, nohup is a special command. The process started with this command does not terminate even if the user logs off from the system.
Question - 30 : - Which mode executes the fault handler?
Answer - 30 : - The Kernel mode.