Concatenate two variable into new one bash

A simple one!

In Bash, you can concatenate two variables into a new one using the following syntax:

new_variable=${variable1}${variable2}

For example:

foo="Hello"
bar="World"
new_variable=${foo}${bar}
echo $new_variable
# Output: HelloWorld

Alternatively, you can use the += operator to concatenate the variables:

new_variable=${foo}${bar}

Or, you can use the printf command:

new_variable=$(printf "%s%s" "$foo" "$bar")

Note that in the last example, the $( ) syntax is used to capture the output of the printf command as a string.