use strict;
my $str = 'TRZ dupa dupa dupa siurak KFR GTB GTT TGH 5 10 15 20:30 5/12/2587
dupa KGB TRZ dupa siurak KFR GTB 5 Jan ssdsdsdsd
dupa KGB TRZ dupa siurak KFR GTB 5 Jan 1235
dupa KGB TRZ dupa siurak KFR GTB 5 January sdsdsdsd
dupa KGB TRZ dupa siurak KFR GTB 5 January 2315';
my $regex = qr/([A-Z]{3})(?:.*?)([A-Z]{3})(?:.*?)((\d{1,2}\/\d{1,2}\/\d{4})|(\d{1,2}(?:.*?)(January|February|March|April|May|June|July|August|September|October|December)( (\d{4}))?)|(\d{1,2}(?:.*?)(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)( (\d{4}))?))/p;
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