The regular expression [\S\s]* in PHP means “don’t match new lines”.
In PHP, the /s flag can be used to make the dot match all the characters −
Example
print(preg_match('/^[\S\s]$/s',"hello \n world"));Output
This will produce the following output −
0
The ‘preg_match’ function is used to match regular expression with the given input string. Here since the ‘\’ is encountered, it returns 0.