re = /(¶[\S\s]*?¶)/m
str = 'This is good text, and should be kept
977
00:36:46,805 --> 00:36:50,874
¶ This is complete junk
And this is also junk, on a second line¶
This is good, and I want to keep it.
¶Garbage on its own line¶
This is good
Good sentence ¶but rubbish inline¶ and this is good
Good
¶ Trash
Rubbish ¶
Good'
subst = ''
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html