Perl Code required to break loop when key pressed -

i have script gets executed, require loop tells process sleep 20-30 secs whilst user runs different test.

once test completed user presses enter continue script halted. if enter not pressed within 20-30 second period script continue run without user input.

i tried following code pauses script indefinitely – not continue after 20 secs, not accept enter.

use term::readkey; readmode 4; {     sleep 20;  } until ( defined( $key = readkey(-1) ) ); readmode 0; 

try while loop instead of do{}

#!usr/bin/perl use strict; use warnings; use term::readkey;  readmode 4;    # turn off controls keys $key;  while ( !defined( $key = readkey(-1) ) ) {     print "no key yet\n";     sleep 5; } print "get key $key\n";  readmode 0;    # reset tty mode before exiting