How to write a regular expression to clean strings from square brackets at the beginning and end?

Question

Regular Expressions

There is a line: [-]
We need a regular expression for cleaning with (preg_replace) from "[]", the most important thing is that "[" is cleaned from the beginning of the line, and "]" from the end.
I tried to do this: "/^[$]/" and "/^\[$\]/", but there is no result.

Answer 1

preg_replace('/^\[(.+)\]$/', '$1', $someString);

Answer 2

Another option