system() behavior different from perl, python, ruby

Could some kind soul tell me why is php's system() function different from the rest of the pack? perl -e "system('man 3 printf');" ruby -e "system('man 3 printf');" python -c "import os; os.system('man 3 printf');" php -r "system('man 3 printf');" In perl, ruby, and python, the above has the same results as typing man 3 printf, IOW the pager takes the terminal and you can browse the man page till you quit the pager. In php, the result is the man page streamed through, and the pager immediately quits. I'm observing this behavior with 4.3.6 but remember seeing this behavior in 4.0.6 or something around that time. PHP 4.3.6 (cli) (built: May 2 2004 20:16:20) Copyright (c) 1997-2004 The PHP Group Zend Engine v1.3.0, Copyright (c) 1998-2004 Zend Technologies