sed + need to remove each line in file that begin with ###

Question

How to remove line that begins with three #

For example need to delete all the following lines: from file

1 ### bla bla bal

2 ###blablabla

3 ### blabla

. . .

THX Yael

Answer 1

cat file | sed '/^###/d'

Answer 2

you can use awk as well

awk '!/^[ \t]*###/' file