for loop with range ({1..10}) in Bash Scripting - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the syntax for i in {1..10} do in a bash script?

It creates a loop that runs 10 times, with the variable i taking values from 1 to 10 in order.

beginner

How do you print numbers 1 to 10 using a for loop with range in bash?

Use:<br>for i in {1..10}; do<br> echo $i<br>done<br>This prints numbers 1 through 10, each on its own line.

intermediate

Can the range in {1..10} be changed to count backwards?

Yes. You can write {10..1} to count down from 10 to 1 in the loop.

intermediate

What happens if you use for i in {1..10..2} in bash?

The loop counts from 1 to 10 in steps of 2, so i takes values 1, 3, 5, 7, 9.

advanced

Why is for i in {1..10} preferred over using seq 1 10 in some cases?

Because {1..10} is a bash brace expansion that is faster and does not require calling an external command like seq.

What will the following bash code print?<br>for i in {1..5}; do echo $((i * 2)); done

A 5 10 15 20 25

B 1 2 3 4 5

C 2 4 6 8 10

D Error

The loop runs from 1 to 5. Each number is multiplied by 2 and printed.

How do you write a for loop in bash to count down from 5 to 1?

A for i in {1..5}; do ... done

B for i in {5..1}; do ... done

C for i in seq 5 1; do ... done

D for i in (5..1); do ... done

Brace expansion {5..1} counts down from 5 to 1.

What does the '..' operator do in {1..10} in bash?

A It creates a list of numbers from 1 to 10

B It performs a subtraction

C It is a syntax error

D It creates a string '1..10'

Brace expansion with '..' generates a sequence of numbers.

Which of these is a valid way to loop over numbers 1 to 10 in bash?

A for i in (1..10); do echo $i; done

B for i in <1..10>; do echo $i; done

C for i in [1..10]; do echo $i; done

D for i in {1..10}; do echo $i; done

Only brace expansion {1..10} is valid syntax for this.

What will for i in {1..10..3} do?

A Loop from 1 to 10 in steps of 3

B Loop from 1 to 3 ten times

C Loop from 3 to 10 in steps of 1

D Syntax error

The third number is the step size in brace expansion.

Explain how to use a for loop with a range in bash to print numbers 1 to 10.

Think about how to write a loop that repeats 10 times with numbers from 1 to 10.

Describe how to modify the range in a bash for loop to count backwards or use steps.

Consider how the numbers inside braces control the loop sequence.