1. In UNIX, what system call is used to create a new file?
a) open()
b) create()
c) makefile()
d) touch()
Answer
Answer: a) open()
Explanation: The open() system call is used to create a new file or open an existing one.
2. Which command is used to list hidden files in UNIX?
a) ls -h
b) ls -a
c) ls -l
d) ls -r
Answer: b) ls -a
Explanation: The ls command with the -a option lists all files, including hidden ones, in UNIX.
3. What is the primary role of the shell in UNIX?
a) File management
b) Memory management
c) Process management
d) User interaction and command execution
Answer: d) User interaction and command execution
Explanation: The shell provides an interface for users to interact with the system and execute commands.
4. Which UNIX command is used to display the contents of a file starting from the end?
a) head
b) tail
c) more
d) less
Answer: b) tail
Explanation: The tail command displays the last part of a file by default in UNIX.
5. What UNIX system call is used to write data to a file?
a) read()
b) write()
c) append()
d) save()
Answer: b) write()
Explanation: The write() system call is used to write data to a file in UNIX.
6. Which command is used to search for occurrences of a pattern in files?
a) grep
b) find
c) locate
d) search
Answer: a) grep
Explanation: The grep command is used to search for occurrences of a pattern in files in UNIX.
7. What is the purpose of the fork() system call in UNIX?
a) Create a new process
b) Terminate the current process
c) Read data from a file
d) Write data to a file
Answer: a) Create a new process
Explanation: The fork() system call creates a new process by duplicating the existing one.
8. Which command is used to display the manual pages for a specific command in UNIX?
a) help
b) man
c) info
d) doc
Answer: b) man
Explanation: The man command displays the manual pages for a specific command in UNIX.
9. What UNIX system call is used to close a file descriptor?
a) close()
b) shutdown()
c) stop()
d) end()
Answer: a) close()
Explanation: The close() system call is used to close a file descriptor in UNIX.
10. Which command is used to rename files in UNIX?
a) move
b) rename
c) mv
d) cp
Answer: c) mv
Explanation: The mv command is used to rename files or move them to a different location in UNIX.
11. What is the function of the chmod command in UNIX?
a) Change file ownership
b) Change file permissions
c) Change file attributes
d) Change file location
Answer: b) Change file permissions
Explanation: The chmod command is used to change the permissions of files and directories in UNIX.
12. Which command is used to display the process status in UNIX?
a) ps
b) top
c) status
d) process
Answer: a) ps
Explanation: The ps command is used to display the process status in UNIX.
13. What UNIX system call is used to change the current working directory to the root directory?
a) chroot()
b) cdroot()
c) rootdir()
d) chdir()
Answer: a) chroot()
Explanation: The chroot() system call is used to change the current working directory to the root directory in UNIX.
14. Which command is used to display the environment variables in UNIX?
a) echo
b) env
c) set
d) vars
Answer: b) env
Explanation: The env command is used to display the environment variables in UNIX.
15. What is the primary role of the inode in UNIX?
a) Represent a directory entry
b) Store file data and metadata
c) Provide access control for files and directories
d) Represent a process in memory
Answer: b) Store file data and metadata
Explanation: An inode in UNIX stores information about a file, including its data blocks and metadata.
16. Which command is used to set or display the file creation mask in UNIX?
a) chmod
b) umask
c) chmask
d) mask
Answer: b) umask
Explanation: The umask command is used to set or display the file creation mask in UNIX.
17. What UNIX system call is used to change the access and modification times of a file?
a) touch()
b) time()
c) utime()
d) mtime()
Answer: c) utime()
Explanation: The utime() system call is used to change the access and modification times of a file in UNIX.
18. Which command is used to create a symbolic link in UNIX?
a) ln -s
b) link -s
c) sym
d) lnk
Answer: a) ln -s
Explanation: The ln command with the -s option is used to create symbolic links in UNIX.
19. What is the purpose of the lseek() system call in UNIX?
a) Read from a file
b) Write to a file
c) Move the file offset
d) Close a file
Answer: c) Move the file offset
Explanation: The lseek() system call is used to move the file offset in UNIX.
20. Which command is used to set or display file timestamps in UNIX?
a) touch
b) time
c) settime
d) timestamp
Answer: a) touch
Explanation: The touch command is used to set or display file timestamps in UNIX.
21. What is the purpose of the exec() system call in UNIX?
a) Create a new process
b) Replace the current process with a new program
c) Read data from a file
d) Write data to a file
Answer: b) Replace the current process with a new program
Explanation: The exec() system call is used to replace the current process with a new program in UNIX.
22. Which command is used to create a new hard link in UNIX?
a) ln
b) link
c) mklink
d) hardlink
Answer: a) ln
Explanation: The ln command is used to create hard links in UNIX.
23. What is the function of the fclose() function in UNIX?
a) Open a file
b) Close a file
c) Read from a file
d) Write to a file
Answer: b) Close a file
Explanation: The fclose() function is used to close a file in UNIX.
24. Which command is used to view the contents of a file one page at a time in UNIX?
a) cat
b) more
c) less
d) tail
Answer: b) more
Explanation: The more command is used to view the contents of a file one page at a time in UNIX.
25. What is the purpose of the mkdir command in UNIX?
a) Display the contents of a directory
b) Create a new directory
c) Remove a directory
d) Rename a directory
Answer: b) Create a new directory
Explanation: The mkdir command is used to create a new directory in UNIX.
26. In UNIX, which command is used to change the ownership of a file?
a) chown
b) chmod
c) chgrp
d) own
Answer: a) chown
Explanation: The chown command is used to change the ownership of a file in UNIX.
27. What is the purpose of the readlink() system call in UNIX?
a) Create a symbolic link
b) Read the contents of a file
c) Read the value of a symbolic link
d) Write data to a file
Answer: c) Read the value of a symbolic link
Explanation: The readlink() system call is used to read the value of a symbolic link in UNIX.
28. Which command is used to display the process ID of the current shell session in UNIX?
a) pid
b) getpid
c) echo
d)ps−p∗∗
Answer:c)echo**
Explanation: The echo $$ command displays the process ID (PID) of the current shell session in UNIX.
29. What is the primary role of the mount command in UNIX?
a) Create a new file system
b) Mount a file system
c) Unmount a file system
d) Check file system integrity
Answer: b) Mount a file system
Explanation: The mount command is used to attach a file system to the system’s directory tree in UNIX.
30. In UNIX, what is the purpose of the umount command?
a) Create a new file system
b) Mount a file system
c) Unmount a file system
d) Check file system integrity
Answer: c) Unmount a file system
Explanation: The umount command is used to detach a mounted file system in UNIX.
31. Which command is used to display the current system time in UNIX?
a) clock
b) time
c) date
d) systemtime
Answer: c) date
Explanation: The date command is used to display the current system time and date in UNIX.
32. What is the function of the mknod command in UNIX?
a) Create a new file
b) Create a new directory
c) Create a special file
d) Create a symbolic link
Answer: c) Create a special file
Explanation: The mknod command is used to create special files, such as device files, in UNIX.
33. Which command is used to display the amount of free and used memory in the system in UNIX?
a) mem
b) free
c) top
d) ps
Answer: b) free
Explanation: The free command is used to display the amount of free and used memory in the system in UNIX.
34. What is the purpose of the sync command in UNIX?
a) Synchronize system clocks
b) Synchronize file system buffers with disk
c) Synchronize user sessions
d) Synchronize network connections
Answer: b) Synchronize file system buffers with disk
Explanation: The sync command is used to flush file system buffers to disk, ensuring data integrity in UNIX.
35. Which command is used to display the routing table in UNIX?
a) route
b) netstat
c) ifconfig
d) arp
Answer: a) route
Explanation: The route command is used to display or manipulate the IP routing table in UNIX.
36. What is the purpose of the grep command in UNIX?
a) Search for files
b) Search for text patterns in files
c) Display file permissions
d) Display file contents
Answer: b) Search for text patterns in files
Explanation: The grep command is used to search for text patterns in files in UNIX.
37. Which command is used to display information about currently logged-in users in UNIX?
a) users
b) who
c) w
d) last
Answer: b) who
Explanation: The who command is used to display information about currently logged-in users in UNIX.
38. What is the purpose of the chsh command in UNIX?
a) Change shell
b) Change ownership of a file
c) Change file permissions
d) Change file attributes
Answer: a) Change shell
Explanation: The chsh command is used to change the login shell for a user in UNIX.
39. Which command is used to display information about CPU usage in UNIX?
a) cpu
b) top
c) ps
d) load
Answer: b) top
Explanation: The top command is used to display real-time information about CPU usage and running processes in UNIX.
40. What is the function of the mkfifo command in UNIX?
a) Create a regular file
b) Create a special file
c) Create a directory
d) Create a named pipe
Answer: d) Create a named pipe
Explanation: The mkfifo command is used to create a named pipe, also known as a FIFO (first in, first out), in UNIX.
41. Which command is used to display information about disk usage in UNIX?
a) du
b) df
c) disk
d) space
Answer: b) df
Explanation: The df command is used to display information about disk usage and available disk space in UNIX.
42. What is the purpose of the renice command in UNIX?
a) Rename a file
b) Change the priority of a running process
c) Change file permissions
d) Change file ownership
Answer: b) Change the priority of a running process
Explanation: The renice command is used to change the priority of a running process in UNIX.
43. Which command is used to display information about system processes in UNIX?
a) ps
b) top
c) pstree
d) process
Answer: a) ps
Explanation: The ps command is used to display information about system processes, including their IDs, states, and resource usage, in UNIX.
44. What is the purpose of the shutdown command in UNIX?
a) Restart the system
b) Power off the system
c) Close user sessions
d) Hibernate the system
Answer: b) Power off the system
Explanation: The shutdown command is used to gracefully power off or reboot the system in UNIX.
45. Which command is used to display information about file system inode usage in UNIX?
a) inodes
b) ls
c) df
d) stat
Answer: a) inodes
Explanation: The inodes command is used to display information about file system inode usage in UNIX.
46. What is the purpose of the syslogd daemon in UNIX?
a) Manage user sessions
b) Manage system logs
c) Manage network connections
d) Manage file permissions
Answer: b) Manage system logs
Explanation: The syslogd daemon is responsible for managing system logs in UNIX.
47. Which command is used to display information about system memory and swap usage in UNIX?
a) meminfo
b) swapinfo
c) free
d) top
Answer: c) free
Explanation: The free command is used to display information about system memory and swap usage in UNIX.
48. What is the purpose of the fsck command in UNIX?
a) Mount a file system
b) Unmount a file system
c) Check and repair file system integrity
d) Create a new file system
Answer: c) Check and repair file system integrity
Explanation: The fsck command is used to check and repair file system integrity in UNIX.
49. Which command is used to display the list of open files and processes that have them open in UNIX?
a) files
b) open
c) lsof
d) fstat
Answer: c) lsof
Explanation: The lsof command is used to display the list of open files and processes that have them open in UNIX.
50. What is the purpose of the kill command in UNIX?
a) Kill a process
b) Remove a file
c) Change file permissions
d) Rename a file
Answer: a) Kill a process
Explanation: The kill command is used to terminate or send signals to processes in UNIX.
