Logical operators (-a, -o, !) in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Bash test command?

Consider the following Bash command:

if [ 5 -gt 3 -a 2 -lt 4 ]; then echo "True"; else echo "False"; fi

What will be printed when this command runs?

Bash Scripting

if [ 5 -gt 3 -a 2 -lt 4 ]; then echo "True"; else echo "False"; fi

A Syntax error

B True

C False

D No output

💡 Hint

Remember that '-a' means AND in Bash test expressions.

The condition checks if 5 is greater than 3 AND 2 is less than 4. Both are true, so the whole condition is true, printing 'True'.

💻 Command Output

intermediate

What does this Bash condition print?

Look at this Bash snippet:

if [ ! 0 -eq 1 ]; then echo "Yes"; else echo "No"; fi

What will be the output?

Bash Scripting

if [ ! 0 -eq 1 ]; then echo "Yes"; else echo "No"; fi

A Yes

B No

C Syntax error

D No output

💡 Hint

The '!' operator negates the condition that follows it.

0 equals 1 is false, negating it with '!' makes the condition true, so it prints 'Yes'.

💻 Command Output

advanced

What is the output of this complex Bash test?

Analyze this Bash command:

if [ 3 -lt 2 -o \( 4 -eq 4 -a ! 5 -gt 10 \) ]; then echo "Pass"; else echo "Fail"; fi

What will it print?

Bash Scripting

if [ 3 -lt 2 -o \( 4 -eq 4 -a ! 5 -gt 10 \) ]; then echo "Pass"; else echo "Fail"; fi

A No output

B Fail

C Syntax error

D Pass

💡 Hint

Remember '-o' means OR, '-a' means AND, and '!' negates the condition. Parentheses group conditions.

3 < 2 is false, but the grouped condition (4 == 4 AND NOT 5 > 10) is true, so overall condition is true, printing 'Pass'.

💻 Command Output

advanced

What error does this Bash test command raise?

What happens when you run this command?

if [ 5 -gt 3 -a ! ]; then echo "OK"; else echo "Not OK"; fi

Bash Scripting

if [ 5 -gt 3 -a ! ]; then echo "OK"; else echo "Not OK"; fi

A Prints Not OK

B Prints OK

C Syntax error

D No output

💡 Hint

The '!' operator must be followed by a condition.

The '!' operator is used without a condition, causing a syntax error in the test expression.

💻 Command Output

expert

What is the value of variable RESULT after running this script?

Given this Bash script:

RESULT=0
if [ ! \( 2 -eq 2 -o 3 -lt 1 \) ]; then RESULT=1; else RESULT=2; fi
echo $RESULT

What will be printed?

Bash Scripting

RESULT=0
if [ ! \( 2 -eq 2 -o 3 -lt 1 \) ]; then RESULT=1; else RESULT=2; fi
echo $RESULT

A Syntax error

B 1

C 2

D 0

💡 Hint

Evaluate inside the parentheses first, then apply the negation.

Inside parentheses: 2 == 2 is true, 3 < 1 is false, so OR is true. Negating true gives false, so else branch runs, RESULT=2.