Linux / Unix questions and answers focuses on Bash Shell programming. It will be useful for both fresher & experienced who are learning Linux Basics, Essentials and Shell programming.
1. What will be output of following command:
$ echo "The process id is" $$$$ a) The process id is $$ b) The process id is $<pid>$<pid> c) The process id is <pid><pid> d) The process id is $$$$
View Answer
Answer: c
Clarification: None.
2. What would be the current working directory at the end of the following command sequence?
$ pwd /home/user1/proj $ cd src $ cd generic $ cd . $ pwd
a) /home/user1/proj
b) /home/user1/proj/src
c) /home/user1
d) /home/user1/proj/src/generic
Answer: d
Clarification: None.
3. How do you print the lines between 5 and 10, both inclusive
a) cat filename | head | tail -6
b) cat filename | head | tail -5
c) cat filename | tail +5 | head
d) cat filename | tail -5 | head -10
Answer: a
Clarification: None.
4. Create a new file “new.txt” that is a concatenation of “file1.txt” and “file2.txt”
a) cp file.txt file2.txt new.txt
b) cat file1.txt file2.txt > new.txt
c) mv file[12].txt new.txt
d) ls file1.txt file2.txt | new.txt
Answer: b
Clarification: None.
5. which of these is NOT a valid variable in bash
a) __ (double underscore)
b) _1var (underscore 1 var )
c) _var_ (underscore var underscore)
d) some-var (some hyphen var)
Answer: d
Clarification: None.
6. What is the output of the following code:
os=Unix echo 1.$os 2."$os" 3.'$os' 4.$os
a) 1.Unix 2.Unix 3.Unix 4.Unix
b) 1.Unix 2.Unix 3.$os 4.Unix
c) 1.Unix 2.Unix 3.Unix 4.$os
d) 1.Unix 2.$os 3.$os 4.$os
Answer: b
Clarification: None.
7. What is the return value ($?) of this code:
os = Unix [$osName = UnixName] && exit 2 [${os}Name = UnixName] && exit 3
a) 0
b) 1
c) 2
d) 3
Answer: d
Clarification: None.
8. What is the output of the following program?
x = 3; y = 5; z = 10; if [( $x -eq 3 ) -a ( $y -eq 5 -o $z -eq 10 )] then echo $x else echo $y fi
a) 1
b) 3
c) 5
d) Error
Answer: b
Clarification: None.
9. What is the output of the following program?
[ -n $HOME ] echo $? [ -z $HOME ] echo $? a) 0 1 b) 1 0 c) 0 0 d) 1 1
View Answer
Answer: a
Clarification: None.
10. What is the output of the following program?
b = [ -n $b ] echo $? [ -z $b ] echo $? a) 1 1 b) 2 2 c) 0 0 d) 0 1
View Answer
Answer: c
Clarification: None.
11. The expression expr -9 % 2 evaluates to:
a) 0
b) 1
c) -1
d) 2
Answer: c
Clarification: None.
12. The statement z = ‘expr 5 / 2’ would store which of the following values in z?
a) 0
b) 1
c) 2
d) 2.5
Answer: c
Clarification: None.