Linux Bash Shell Questions & Answers on Arithmetic Expressions for Freshers

1. Which built-in command performs integer arithmetic in bash shell?

a) let
b) get
c) set
d) none of the mentioned

Answer: a

2. Which expression use the value of the enclosed arithmetic expression?

a) $(())
b) $()
c) ${}
d) $[].

Answer: a

3. If a and b are 2 variables then the meaning of a<<=b is
a) b = a << b
b) a = a << b
c) b = b << a
d) a = a << b

Answer: b

4. Which one of the following is bitwise ‘exclusive or’ operator?

a) ^=
b) |=
c) !=
d) none of the mentioned

Answer: a

5. Which one of the following is not a valid operator in bash shell?

a) ||
b) ~
c) =<<
d) -=

Answer: c

6. What is the output of this program?

1.    #!/bin/bash

2.    a=2

3.    b=4

4.    let c=a**b

5.    echo $c

6.    exit 0

a) 8
b) 16
c) 32
d) none of the mentioned

Answer: b

Explanation:’**’ is the exponentation operator in bash shell.

Output:
root@ubuntu:/home/sanfoundry#./test.sh
16
root@ubuntu:/home/sanfoundry#

7. What is the output of this program?

1.    #!/bin/bash

2.    a=10; b=20

3.    c=$((++a))

4.    let a=c+a

5.    echo $a

6.    exit 0

a) 21
b) 22
c) program will generate an error message
d) none of the mentioned

Answer: b

Output:
root@ubuntu:/home/sanfoundry#./test.sh
22
root@ubuntu:/home/sanfoundry#

8. What is the output of this program?

1.    #!/bin/bash

2.    a=10

3.    b=$(( $a<0?10:$a<100 ))

4.    echo $b

5.    exit 0

a) 10
b) 20
c) 1
d) 0

Answer: c

Explanation: Firstly the ‘$a<0 1.="" and="" because="" been="" checked.="" checked="" colon="" condition="" div="" false="" hand="" has="" hence="" is="" it="" of="" output="" program="" right="" side="" so="" the="" this="" true="">

Output:
root@ubuntu:/home/sanfoundry# ./test.sh
1
root@ubuntu:/home/sanfoundry#

9. What is the output of this program?

1.    #!/bin/bash

2.    a=10

3.    b=$(( $a<0&&$a<100 ))

4.    echo $b

5.    exit 0

a) 10
b) 0
c) 1
d) none of the mentioned

Answer: b

Explanation: The condition ‘$a<0 0.="" and="" div="" false="" is="" logical="" operator="" output="" provides="" so="" the="">

Output:
root@ubuntu:/home/sanfoundry# ./test.sh
0
root@ubuntu:/home/sanfoundry#

10. What is the output of this program?

1.     #!/bin/bash

2.     a=1; b=2; c=3

3.     d=$(( ++a**b*c++ + a ))

4.     echo $d

5.     exit 0

a) 14
b) 12
c) program will generate an error message
d) none of the mentioned

Answer: a

Explanation: The operators in decreasing order of precedence are ++, **, *, +.

Output:
root@ubuntu:/home/sanfoundry# ./test.sh
14
root@ubuntu:/home/sanfoundry#