^start of line
#the literal # (3510 / 438 / 2316)
\s*any whitespace character, repeated any number of times
User@Host:the literal text User@Host: (case sensitive) \s*any whitespace character, repeated any number of times
rootthe literal text root (case sensitive) \[the literal [ (9110 / 1338 / 5B16)
rootthe literal text root (case sensitive) \]the literal ] (9310 / 1358 / 5D16)
\s*any whitespace character, repeated any number of times
@the literal @ (6410 / 1008 / 4016)
\s*any whitespace character, repeated any number of times
localhostthe literal text localhost (case sensitive) \s*any whitespace character, repeated any number of times
\[the literal [ (9110 / 1338 / 5B16)
\]the literal ] (9310 / 1358 / 5D16)
$end of line
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