Which symbol is used to build arrays in Shell Scripts?

In shell scripting, the symbol that is used to denote and build arrays is the pair of braces with a dollar sign, ${}. This syntax is fundamental when working with indexed arrays or associative arrays in bash scripting.

When you want to define an array or access its elements, you typically use this notation to ensure that the shell correctly interprets variable names and their associated array indexes. For example, to create an array, you might use the syntax my_array=(value1 value2 value3) for indexed arrays or declare an associative array as declare -A my_array.

Using ${} syntax allows for specific variable referencing and helps prevent ambiguity in your scripts, particularly in more complex expressions. For instance, to access the first value of the array, you would write ${my_array[0]}.

The other symbols have different purposes in shell scripting:

• The curly braces {} themselves are used for grouping commands, but without the dollar sign, they don't relate to array definitions.
• Square brackets [] commonly designate test conditions or used for array indexing in some contexts, but by themselves, they do not define arrays.
• Parentheses () are used for defining subshells or grouping commands but not for building arrays.

Understanding the proper syntax and structures