while loop in Bash Scripting - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a while loop in bash scripting?

A while loop repeats a block of commands as long as a given condition is true. It helps automate repeated tasks until the condition changes.

beginner

How do you write a basic while loop in bash?

Use this structure:<br>

while [ condition ]; do<br>  commands<br>done

<br>The commands run repeatedly while the condition is true.

intermediate

What happens if the while loop condition is never false?

The loop runs forever, creating an infinite loop. You must include a way to stop it, like changing a variable inside the loop or using break.

intermediate

How can you stop a while loop early in bash?

Use the break command inside the loop to exit immediately, even if the condition is still true.

beginner

Why is it important to update variables inside a while loop?

Updating variables changes the condition over time. Without this, the loop might never end because the condition stays true forever.

What keyword starts a loop that runs while a condition is true in bash?

A while

B for

C if

D case

The while keyword starts a loop that runs as long as the condition is true.

Which command stops a while loop immediately inside the loop?

A continue

B break

C exit

D stop

The break command exits the loop immediately.

What happens if the condition in a while loop never becomes false?

A The loop runs forever (infinite loop)

B The loop stops immediately

C The loop runs once

D The script crashes

If the condition never becomes false, the loop runs forever, causing an infinite loop.

Which symbol is used to test conditions inside a while loop in bash?

A {}

B ()

C <>

D []

Square brackets [] are used to test conditions in bash.

How do you write a while loop that counts from 1 to 5 in bash?

A if [ $i -le 5 ]; then echo $i; fi

B while (i <= 5) { echo i; i++; }

C i=1; while [ $i -le 5 ]; do echo $i; ((i++)); done

D for i in 1..5; do echo $i; done

Option C shows the correct bash syntax for a while loop counting from 1 to 5.

Explain how a while loop works in bash and why updating variables inside it is important.

Think about how the loop knows when to stop.

Describe how to safely stop a while loop before its condition becomes false.

Consider commands that control loop flow.