use strict;
my $str = '7
00: 00: 20,509 -> 00: 00: 25,059
on the data before and does not shy in front of radical solutions such as post privacy back.
8
00: 00: 25,159 -> 00: 00: 27,896
On his blog writes: sower already since 2011
9
00: 00: 27,996 -> 00: 00: 31,784
on the impact of technology on society, politics and economy.';
my $regex = qr/((?:(?<=:)|(?<=->)) | (?=->))/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