How to concatenate string variables in Bash

Question

In PHP, strings are concatenated together as follows:

$foo = "Hello"; $foo .= " World"; 

Here, $foo becomes "Hello World".

How is this accomplished in Bash?

Answer 1

foo="Hello" foo="${foo} World" echo "${foo}" > Hello World 

In general to concatenate two variables you can just write them one after another:

a='Hello' b='World' c="${a} ${b}" echo "${c}" > Hello World 

Answer 2

Bash also supports a += operator as shown in this code:

A="X Y" A+=" Z" echo "$A" 

output

X Y Z