Avoid the shell. In addition to the usual benefits, this problem goes away.
You should use IPC::Run3 or IPC::Run, but low-level IPC::Open3 will be easy enough to use here.
use File::Spec::Functions qw( devnull );
use IPC::Open3 qw( open3 );
{
my @cmd = (
$tshark_binary => (
-r => $pcap,
-e => "frame.number",
-e => "frame.time_epoch",
-e => "ip.src",
-e => "ip.id",
-T => "text",
-T => "fields",
-E => "separator=,"
),
);
open(local *CHILD_STDIN, '<', devnull) or die $!;
open(local *CHILD_STDOUT, '>', $file_temp) or die $!;
my $pid =
open3('<&CHILD_STDIN', '>&CHILD_STDOUT', '>&STDERR', @cmd);
waitpid($pid, 0);
}