Regular Expressions 101

Pro

subthe literal text sub (case sensitive)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

domainthe literal text domain (case sensitive)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

comthe literal text com (case sensitive)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

enthe literal text en (case sensitive)

Group 1(\/|#){0,2}

{0,2}repeats the group contents below between 0 and 2 times:

1st Alternative\/

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

2nd Alternative#

#the literal # (35₁₀ / 43₈ / 23₁₆)

$end of line

Global pattern flags

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

Detailed match information will be displayed here automatically.

26 tokens

Regular Expression

sub\.domain\.com\/en(\/|#){0,2}$

New

sub.domain.com/en
sub.domain.com/en/
sub.domain.com/en/#
sub.domain.com/en#
sub.domain.com/en/something-else
sub.domain.com/en#or-this
This is a bonus: 
sub.domain.com/en#/
Check the /1 version if you don't like it.