split and matching

[perllearner007]

I have tab delim file as follows

#file1
#version1.1
#columns with the information as follows
state1    class1     report_version_1.1    9428    4567   .    .   cal
+l=1;times=5;toss=head->tail;sno=A1B1;effect=positive
state1    class1     report_version_1.1    3862    4877   .    .   cal
+l=1;times=5;toss=head->tail;sno=A1B2;effect=negative
state1    class1     report_version_1.1    2376    4567   .    .   cal
+l=1;times=5;toss=head->tail;sno=;effect=positive
state2    class1     report_version_1.1    4378    2345   .    .   cal
+l=1;times=5;toss=tail->tail;sno=A1B3;effect=positive,negative, both
state2    class1     report_version_1.1    1289    4835   .    .   cal
+l=1;times=5;toss=head->tail;sno=;effect=positive

Note: There are no column headers in the file just the three top comments.
I am trying to parse out the 8 column(starting from call=1) which is basically a string separated by semi colons. I need to remove all the entries that have part1: no sno (value/name) (for eg: for 3 row sno=; i.e there is no record) and also part2: those that have same toss results i.e toss=tail->tail is not needed since both are tail. Since I am learning perl I try and divide such things in parts and hence Here is what I have come up with so far for the part1: sno…

#!usr/bin/perl
use warnings;

#inputfile
my $input_file = "/Users/myfolder/myfile.txt";
die "Cannot open $input_file \n" unless (open(IN, $input_file));
#open file
my @LINES =<IN>;
#output file
#Open output file and write the needed results
die "output1.txt" unless(open( OUT,"> output1.txt"));

my @infos;
while(<IN>){

        
my @fields = split ';', $_;

my $state = $fields[1];
my $class1 = $fields[2];
my $report_version_1.1 = $fields[3];
my $value1 = $fields[4];
my $value2 = $fields[5];
my $dot1 = $fields[6];
my $dot2 = $fields[7];
my $info = $fields[8];

if ( $fields[8] =~ /^[sno]/ =~ /^[sno]/ ) {

push @infos, $_;
print OUT " $state\ $class\ $report_version_1.1\ $value1\ $value2\ $do
+t1 \ $dot2 \ $info\n";
}
        
}
exit;

Any other better ways to solve this for both sno and toss parts together?