break and continue in Bash Scripting - Step-by-Step Execution

Concept Flow - break and continue

Start Loop

↓

Check Condition

Yes↓

Inside Loop Body

↓

If 'continue' condition?

Yes→Skip rest, go to next iteration

↓

If 'break' condition?

Yes→Exit Loop

↓

Execute remaining code

↓

Next iteration

↩Back to Check Condition

The loop starts and checks its condition. Inside the loop, if 'continue' is triggered, it skips to the next iteration. If 'break' is triggered, it exits the loop immediately. Otherwise, it runs the remaining code and repeats.

Execution Sample

Bash Scripting

for i in {1..5}; do
  if [ "$i" -eq 3 ]; then
    continue
  fi
  if [ "$i" -eq 4 ]; then
    break
  fi
  echo $i
done

This loop prints numbers 1 to 5 but skips 3 and stops completely at 4.

Execution Table

Iteration	i	Condition 'i==3'	Action	Condition 'i==4'	Action	Output
1	1	False	No continue	False	No break	1
2	2	False	No continue	False	No break	2
3	3	True	Continue (skip echo)	N/A	N/A
4	4	False	No continue	True	Break (exit loop)

💡 Loop exits at iteration 4 because break condition is met.

Variable Tracker

Variable	Start	After 1	After 2	After 3	After 4	Final
i	N/A	1	2	3	4	Loop exited

Key Moments - 3 Insights

Why is there no output when i equals 3?

At iteration 3 in the execution_table, the 'continue' condition is true, so the loop skips the echo command and moves to the next iteration without printing.

Why does the loop stop completely at i equals 4?

At iteration 4, the 'break' condition is true, so the loop exits immediately, stopping any further iterations as shown in the execution_table.

Does 'continue' stop the entire loop?

No, 'continue' only skips the rest of the current loop iteration and moves to the next one, unlike 'break' which exits the loop entirely, as seen in the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the output when i equals 3?

A 3

B No output

C 4

D Error

💡 Hint

Check the 'Action' column for iteration 3 where 'continue' skips the echo.

At which iteration does the loop stop running?

A 2

B 3

C 4

D 5

💡 Hint

Look at the 'Action' column for 'break' condition in the execution_table.

If we remove the 'continue' condition, what would be the output at iteration 3?

A 3

B No output

C Loop breaks

D Error

💡 Hint

Without 'continue', the echo command runs normally at iteration 3 as per the variable_tracker.

Concept Snapshot

break and continue in bash loops:
- 'continue' skips the rest of current iteration, moves to next
- 'break' exits the loop immediately
- Use inside loops with if conditions
- Helps control loop flow clearly and simply

Full Transcript

This example shows a bash for loop from 1 to 5. When the variable i equals 3, the script uses 'continue' to skip printing 3 and move to the next number. When i equals 4, the script uses 'break' to stop the loop completely. The execution_table traces each iteration, showing variable values, conditions checked, actions taken, and output produced. The variable_tracker shows how i changes each step. Key moments clarify why output is missing at 3 and why the loop stops at 4. The quiz tests understanding of these behaviors by referencing the execution_table and variable_tracker.

Practice

1. What does the break command do inside a bash loop?

easy

A. Pauses the loop until user input

B. Stops the loop immediately and exits it

C. Restarts the loop from the beginning

D. Skips the current iteration and continues with the next

Solution

1. Step 1: Understand the role of break in loops

   The break command immediately stops the loop and exits it, no matter where it is in the loop.

2. Step 2: Compare with other commands

   continue skips to the next iteration, but break stops the loop entirely.

3. Final Answer:

   Stops the loop immediately and exits it -> Option B

4. Quick Check:

   break stops loop = D [OK]

Hint: Break means stop loop now, continue means skip one round [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break skips iteration instead of stopping
• Assuming break restarts the loop

2. Which of the following is the correct syntax to skip the current iteration in a bash for loop?

easy

A. break

B. skip

C. continue

D. next

Solution

1. Step 1: Identify the command to skip iteration

   In bash, continue is used to skip the current iteration and move to the next one.

2. Step 2: Check other options

   break stops the loop, skip and next are not valid bash commands.

3. Final Answer:

   continue -> Option C

4. Quick Check:

   Skip iteration = continue [OK]

Hint: Use continue to skip current loop round in bash [OK]

Common Mistakes:

• Using break instead of continue
• Using non-existent commands like skip or next
• Confusing syntax with other languages

3. What will be the output of this bash script?

for i in 1 2 3 4 5; do
  if [ "$i" -eq 3 ]; then
    break
  fi
  echo $i
done

medium

A. 1 2 3 4 5

B. 3 4 5

C. 1 2 3

D. 1 2

Solution

1. Step 1: Analyze the loop and break condition

   The loop runs from 1 to 5. When i equals 3, the break command stops the loop immediately.

2. Step 2: Determine which values are printed

   Before reaching 3, the script echoes 1 and 2. When i is 3, loop breaks, so 3 is not printed.

3. Final Answer:

   1 2 -> Option D

4. Quick Check:

   Break stops at 3, prints before = 1 2 [OK]

Hint: Break stops loop before printing current value [OK]

Common Mistakes:

• Including the break value in output
• Confusing break with continue
• Assuming loop runs fully

4. Identify the error in this bash script snippet:

for i in 1 2 3 4; do
  if [ $i -eq 2 ]
    continue
  fi
  echo $i
done

medium

A. Missing then keyword after if condition

B. Missing semicolon before continue

C. continue cannot be used inside if

D. echo command is misplaced

Solution

1. Step 1: Check if statement syntax

   The if statement requires a then keyword after the condition before commands.

2. Step 2: Identify missing keyword

   The script misses then after [ $i -eq 2 ], causing syntax error.

3. Final Answer:

   Missing then keyword after if condition -> Option A

4. Quick Check:

   If needs then before commands [OK]

Hint: Always put then after if condition in bash [OK]

Common Mistakes:

• Omitting then after if
• Assuming continue needs semicolon
• Thinking continue can't be inside if

5. You want to print numbers 1 to 5 but skip 3 and stop the loop if number is greater than 4. Which code snippet achieves this?

hard

A. for i in 1 2 3 4 5; do
if [ "$i" -eq 3 ]; then continue; fi
if [ "$i" -gt 4 ]; then break; fi
echo $i
done

B. for i in 1 2 3 4 5; do
if [ "$i" -gt 4 ]; then continue; fi
if [ "$i" -eq 3 ]; then break; fi
echo $i
done

C. for i in 1 2 3 4 5; do
if [ "$i" -eq 3 ]; then break; fi
if [ "$i" -gt 4 ]; then continue; fi
echo $i
done

D. for i in 1 2 3 4 5; do
if [ "$i" -eq 3 ]; then continue; fi
if [ "$i" -gt 4 ]; then continue; fi
echo $i
done

Solution

1. Step 1: Understand requirements

   Skip printing 3 (use continue), stop loop if number > 4 (use break).

2. Step 2: Analyze each option

   for i in 1 2 3 4 5; do if [ "$i" -eq 3 ]; then continue; fi if [ "$i" -gt 4 ]; then break; fi echo $i done correctly uses continue to skip 3 and break to stop after 4. Others misuse break and continue or reverse conditions.

3. Final Answer:

   Option A code snippet -> Option A

4. Quick Check:

   continue skips 3, break stops after 4 [OK]

Hint: Use continue to skip, break to stop loop [OK]

Common Mistakes:

• Swapping break and continue logic
• Wrong condition order causing wrong output
• Not stopping loop after number > 4