Use IPC::Open3.

use IPC::Open3 'open3';

$SIG{CHLD} = 'IGNORE'; # see perlipc for the scoop
open3( undef, my $ham_fh, my $ham_err_fh,
       'find', $CUR_INBOX, '-type', 'f' );
<$ham_err_fh> or warn "Error!\n";

@ham = <$ham_fh>;
[download]