use strict;
my $str = '{"eventType":"delete","ServerSerial":"1556562030","ServerName":"XYZ_U_O","deletedat":"2018-08-24 17:56:39.974"}
{"eventType":"delete","ServerSerial":"0","ServerName":"","deletedat":"2018-08-24 17:56:34.944"}';
my $regex = qr/{"eventType":"delete","ServerSerial":"0","ServerName":""[^}]+},?/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