Bash Split String into Array (With Delimiters, Newlines & Examples)

If you have a string in Bash and want to split it into an array, this guide gives you the fastest working commands first, followed by optional advanced methods if you need more control.

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Quick Answer: Bash Split String into Array (Recommended)

string="apple banana orange"
read -ra arr <<< "$string"
echo "${arr[@]}"

✔ Works in Bash
✔ Splits on whitespace
✔ Safe for most scripts

For most Bash scripts, this is the recommended and sufficient solution.

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Common Mistakes When Splitting Strings in Bash

# ❌ Don't do this
arr=($string)

Why it’s dangerous:

• Breaks on spaces inside values
• Fails with special characters
• Unsafe for user input

⚠️ Note: Arrays are a Bash feature. POSIX shells like sh do not support arrays. If your script uses #!/bin/sh, these methods will not work.

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Split String into Array Using a Delimiter

Use IFS (Internal Field Separator) when your string uses a custom delimiter.

Comma-separated string

IFS=',' read -ra arr <<< "apple,banana,orange"

Pipe-separated string

IFS='|' read -ra arr <<< "apple|banana|orange"

Semicolon-separated string

IFS=';' read -ra arr <<< "apple;banana;orange"

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Split Multi-Line String into Array (Best Practice)

For strings containing newlines, mapfile (also called readarray) is the safest and cleanest method.

string=$'apple\nbanana\norange'
mapfile -t arr <<< "$string"

echo "${arr[@]}"

Why this method is preferred:

• No IFS side effects
• Handles multi-line input reliably
• Ideal for files and command output

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Which Method Should You Use?

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Advanced Methods (Optional)

The methods below are not required for most use cases. Use them only when the quick solutions above do not fit your requirement.

Using Parentheses (Simple but Limited)

#!/bin/bash

# Defining a string
string="apple banana orange"

# Splitting the string into an array
myvar=($string)

# Output the array and its length
echo "My array: ${myvar[@]}"
echo "Number of elements in the array: ${#myvar[@]}"

Limitations:

• Splits only on whitespace
• No custom delimiter support
• Word splitting can cause issues with special characters

⚠ Avoid this method when handling untrusted input or strings containing special characters.

Using Loops for Full Control

#!/bin/bash

# Define a string
string="apple banana orange"

# Initialize an empty array
myvar=()

# Use loop to bash convert string to array
for word in $string; do
    myvar+=("$word")
done

# Output the array and its length
echo "My array: ${myvar[@]}"
echo "Number of elements in the array: ${#myvar[@]}"

Use this approach when:

• You need conditional logic
• You want to modify elements while splitting

Using tr (translate or delete characters) for Pre-Processing

string="apple|banana|orange"
string=$(echo "$string" | tr '|' ' ')
read -ra arr <<< "$string"

This is useful when input delimiters must be transformed before splitting.

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Frequently Asked Questions

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Summary

To split a string into an array in Bash:

• Use mapfile for multi-line input
• Use read -ra for space-separated strings
• Use IFS + read for custom delimiters

For further in-depth study and exploration of these topics, you may refer to the official GNU Bash documentation:

• Bash Manual
• Advanced Bash Scripting Guide
• Bash Pitfalls (common issues and challenges encountered in Bash scripting)
• man page of tr
• man page of read
• What is IFS in Bash?