How to remove characters at the beginning and end of a string with a regex?

Question

Regular Expressions

I can’t find a solution to 2 questions in any way:
1. Delete characters at the beginning and end of the line:
it was -

#слово#
#второе слово#

should be -

слово
второе слово

2. Delete lines starting with a set of characters - $1$ or $HEX[ (it's better to delete one of the sets at once)

Answer 1

One option like this:
Several options like this, where the options are grouped (?:1|2|3|4|5):
The result will be like a cut, i.e. a substring.

Your examples:

https://regex101.com/r/q5HvUp/2