I am trying to make simple regex that will check if a line is blank or not.
" some" // not blank " " //blank "" // blank
The pattern you want is something like this in multiline mode:
^is the beginning of string anchor
$is the end of string anchor
\sis the whitespace character class
*is zero-or-more repetition of
In multiline mode,
$ also match the beginning and end of the line.