my $z = `ps -ef | grep syslog | grep -v grep | wc -l`;

system doesnt return the STDOUT instead it returns "the exit status of the program as returned by the wait call.". So the result of the pipes was showing up before any "Content-Type: " output

huck is correct about what is wrong with using system for this task. The rest of my answer is almost identical to here, including the link to this guide:

If and only if the external command you want to run is always a fixed string, then one way to do what you want would be:

use IPC::System::Simple qw/capture/;
my $output = capture('ps -ef | grep syslog | grep -v grep | wc -l');
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However, as I said, this is only a good idea for fixed strings, because otherwise you may introduce security issues! I wrote about the topic of running external commands at length here.

"...alternatives..."

Avoiding to shell out might be one:

#!/usr/bin/env perl

#       $Id: procs.pl,v 1.2 2017/08/02 07:39:39 karl Exp karl $
# http://perlmonks.org/?node_id=1196387

use strict;
use warnings;
use feature qw(say );
use Proc::ProcessTable;
use Data::Dump;

my $cmndline  = qr(syslog);
my @processes = @{ Proc::ProcessTable->new->table };

for my $process (@processes) {
    say $process->cmndline;
}

# dd \@processes;

my $found =
  grep { $_->cmndline =~ /$cmndline/ } @processes;

say $found;

__END__
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See also Proc::ProcessTable.

Regards, Karl

ps -ef | grep -c syslo[g]
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i did