This help?

use warnings;
use strict;
while (<DATA>) {

  #everything before the #
  /^[^#]*/;
  print 'everything before the #: ' . "$&\n";
  
  #everything from the # to the end of the line
  /#.*/;
  print '/#.*/: ' . "$&\n";
  print "\n";
}

#outputs: 
#everything before the #: blah 
#/#.*/: #this is a comment
#
#everything before the #: foo blah 
#/#.*/: #this is a comment
#
#everything before the #: foo bar blah blah blah 
#/#.*/: #this is a comment
#
#everything before the #: 
#
#/#.*/: 
#
__DATA__
blah #this is a comment
foo blah #this is a comment
foo bar blah blah blah #this is a comment
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