^start of line
Negated Character Class[^\s#]+ +matches at least one character outside the set below:
\sa Unicode whitespace character
#the literal # (3510 / 438 / 2316)
\s+a Unicode whitespace character, repeated at least once
/tmpthe literal text /tmp (case sensitive) \s+a Unicode whitespace character, repeated at least once
\S+any character that is not Unicode whitespace, repeated at least once
\s+a Unicode whitespace character, repeated at least once
\S+any character that is not Unicode whitespace, repeated at least once
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string