Extract string from brackets

Question

I\'m pretty new at bash so this is a pretty noob question..

Suppose I have a string:

string1 [string2] string3 string4

I would like

Answer 1

Specify awk multiple delimiters with -F '[delimiters]'

If the delimiters are square brackets, put them back to back like this ][

awk -F '[][]' '{print $2}'

otherwise you will have to escape them

awk -F '[\\[\\]]' '{print $2}'

Other examples to get the value between the brackets:

echo "string1 (string2) string3" | awk -F '[()]' '{print $2}'
echo "string1 {string2} string3" | awk -F '[{}]' '{print $2}'