250+ TOP MCQs on Shell Redirection and Answers

Linux / Unix interview questions and answers focuses on Bash Shell programming & administration. It will be useful for both fresher & experienced preparing interviews on Linux Basics, Essentials and Shell programming.

1. The redirection 2> abc implies
a) Write file 2 to file abc
b) Write standard output to abc
c) Write standard error to abc
d) None of the mentioned
Answer: c
Clarification: None.

2. cmd 2>&1 > abc will
a) Write file2 to file1
b) Write standard output and standard error to abc
c) Write standard error to abc
d) Write standard output to abc & standard error to monitor
Answer: d
Clarification: None.

3. cmd > abc 2>&1 will
a) Write file2 to file1
b) Write standard output and standard error to abc
c) Write standard error to abc
d) Write standard output to abc & standard error to monitor
Answer: b
Clarification: None.

4. Which of these is the correct method for appending “foo” in /tmp/bar file?
a) echo foo > /tmp/bar
b) echo foo >> /tmp/bar
c) echo foo | /tmp/var
d) /tmp/bar < echo foo
Answer: b
Clarification: None.

5. Syntax to suppress the display of command error to monitor?
a) command > &2
b) command 2> &1
c) command 2> &2
d) command 2> /dev/null
Answer: d
Clarification: None.

6. The following commands gives the output like this

    #cat file1 file2
    #cat: file1: No such file or directory
    hello
    If we execute the command “cat file1 file2  1>2  2>&1” the output would be

a) cat: file1: No such file or directory hello
b) No output is displayed
c) Cat: 1>2: No such file or directory
d) hello
Answer: b
Clarification: None.

7. cat < file1 >> file2 | file3
a) file1 content will be appended to file2 and finally stored in file3
b) file1 content will be appended to file2 and file3 will be ignored
c) file2 and file3 will have same content
d) syntax error
Answer: d
Clarification: None.

8. Executing cat /etc/password > /dev/sda as superuser will
a) Write data into a regular file called /dev/sda
b) Write data to the physical device sda
c) Create a temporary file /dev/sda and write data to it
d) None of the mentioned
Answer: b
Clarification: None.

9. From where would the read statement read if the following statements were executed?

   exec < file1
   exec < file2
   exec < file3
   read line

a) It would read all the files
b) It would not read any files
c) It would read all the files in reverse order
d) It would read only file3
Answer: b
Clarification: None.