perl -E "@a1=qw(1 2 3); @a2=qw(a b c d e); say for (@a1 & @a2)"

1

perl -E "@a1=qw(1 2 3); @a2=qw(a b c d e); say for (@a1 , @a2)"

1
2
3
a
b
c
d
e

##</code><code>##

open(FILE, "<x.log");
close (FILE);

# has to be

open my $file_handle, '<', 'x.log' or die "unable to open 'x.log' $!";
..
close $file_handle;


##</code><code>##


my @array;
...
#push 1

push @array, $_ for grep{..

#push 2

push @array, $_ for grep{..


##</code><code>##

# pseudocode

my %report;

foreach my $line( $fh_one ){
 if... matching..
   extract the part interesting

   $report{  $interesting_part  }[0] = 1;  # first file populates the element 0


foreach my $line( $fh_two ){
 if... matching..
   extract the part interesting

   $report{  $interesting_part  }[1] = 1;  # first file populates the element 1 

   
# result like

%report = (

    interesting1 = [ undef, 1 ], # is present only in the second file
    interesting2 = [ 1, undef ], # is present only in the first file
    interesting3 = [ 1, 1 ],     # is present in both files
);