Top 550+ Solved Operating System Architecture MCQ Questions Answer

From 616 to 627 of 627

Q. Which of are following internal commands is used in mail to forward mail to user in user-list?

a. r user-list

b. m user-list

c. d user-list

d. e user-list

  • b. m user-list

Q. Which of the following features of UNIX may be used for inter process communication?

a. signals

b. pipes

c. semaphore

d. all of these

  • d. all of these

Q. The command echo welcome > /dev / tty

a. echoes welcome in all the terminals that are switched on.

b. echoes welcome in all the terminals that are logged on.

c. echoes welcome only in the terminal in which it is run.

d. both (a) and ©

  • d. both (a) and ©

Q. dev/null

a. is a file

b. has write permission for all

c. is the unix built- in dustbin

d. all of these

  • d. all of these

Q. The permission bits of a file noname. can be set to _rws_ _x_ _x by the command.

a. chmod 711 noname

b. chmod go -rw noname

c. chmod 2711 noname

d. none of the above

  • d. none of the above

Q. /bin/passwd has the user execution permission set to 's' because

a. this facility assigns to the user, permissions of the program owner. temporarily

b. it should allow users who don\t have write permission to/etc/passwd to write to it

c. /etc/passwd is write protected

d. all of these

  • d. all of these

Q. If one doesn't want anyone else to read or write to a file named datfile, except through a program in a file filex , then he may use

a. chmod u+s filex ; chmod go_rw datfile

b. chmod 4711 filex ; chmod go_rw datfile

c. chmod 4711 datfile ; chmod go_rw filex

d. both (a) and (b)

  • d. both (a) and (b)

Q. Writing a C program that accepts input from keyboard, rather than from a file is advantageous because

a. keyboard is a file that is already open

b. it can be used in a pipe, if it writes to stdout

c. both (a) and (b)

d. none of the above

  • c. both (a) and (b)

Q. Consider the program main ( ){printf("He arose a victor from\n"); system ("date") ;printf("the dark domain");}If a.out is the executable code corresponding to the above source code, then the command a.out > out f

a. redirects the output of date to file out f

b. displays the output of date on the screen

c. prints everything on the screen

d. prints the two messages on the screen

  • a. redirects the output of date to file out f
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