use strict;
my $str = '5/25/2022 14:13:05
5/25/2022 13:21:07 EDT
5/25/2022 17:07:39 GMT+01:00';
my $regex = qr/^((?:\d{1,2}\/){2}\d{4}\s+(?:\d{1,2}:){2}\d{1,2}).*/mp;
my $subst = '$1';
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