How to Concatenate Strings in Bash: Simple Syntax and Examples

In Bash, you concatenate strings simply by placing them next to each other, like str1="Hello" and str2="World", then result="$str1$str2". You can also add spaces or other characters between strings by including them inside the quotes.

Syntax

To join strings in Bash, you just write them one after another inside double quotes or variables. No special operator is needed.

• str1="Hello": Assign first string.
• str2="World": Assign second string.
• result="$str1$str2": Concatenate both strings.

bash

str1="Hello"
str2="World"
result="$str1$str2"
echo "$result"

Output

HelloWorld

Example

This example shows how to join two strings with a space between them by adding a space character inside the quotes.

bash

greeting="Hello"
name="Alice"
full_greeting="$greeting, $name!"
echo "$full_greeting"

Output

Hello, Alice!

Common Pitfalls

One common mistake is forgetting to use double quotes around variables, which can cause word splitting or unexpected results. Another is trying to use the plus sign + like in other languages, which does not work in Bash.

bash

# Wrong way (will not concatenate):
str1="Hello"
str2="World"
result=$str1$str2
echo "$result"

# Right way:
result="$str1$str2"
echo "$result"

Output

HelloWorld
HelloWorld

Quick Reference

Remember these tips for string concatenation in Bash:

• Place variables side by side inside double quotes to join.
• Add spaces or punctuation inside quotes as needed.
• Always quote variables to avoid word splitting.
• Do not use + for concatenation.

Key Takeaways

Concatenate strings by placing variables side by side inside double quotes.

Include spaces or punctuation inside quotes to format the result.

Always quote variables to prevent word splitting and errors.

Do not use plus signs (+) for string concatenation in Bash.