use strict;
my $str = 'The moment #BTC, we have all $BTC been waiting for:We are happy to announce NIX Platform is rebranding to.. $NBT > $VOICE $NIX > $MUTE $ETH $BTC #BTC';
my $regex = qr/[#$][^\s$#]+(?=(?:\s+[^\w\s]\S*)*\s*$)/mp;
my $subst = '';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
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 Perl, please visit: http://perldoc.perl.org/perlre.html