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  1. <?php
  2. $list = [];
  3. echo empty($list) ? '空': '不空';
  4. echo system(cmd);
  5. ?>
Success #stdin #stdout #stderr 0.04s 25796KB
comments (?)
stdin 
45
stdout 
空
stderr 
PHP Warning:  Use of undefined constant cmd - assumed 'cmd' (this will throw an Error in a future version of PHP) in /home/o7tNj9/prog.php on line 4
sh: 1: cmd: not found
https://ideone.com/8cpHpk
language:
PHP (php 7.3.5)
created:
9 days ago
visibility:
public

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