PHP was initially a HTML preprocessor, and the interprreter only executes code inside
?> tags; the rest is left untouched. The way you are using it now, php would just print the text
phpinfo() back to you.
But it doesn't do so because it is waiting for the rest of the page to be input, and will delay execution until it reaches "end of file". On Windows this means you have to enter Ctrl-Z on a line by itself.
That, and your input is missing the "end of statement" marker – the
If you want to use "interactive" mode as in Python or Ruby's
irb, you need to run
php -a, which will execute every line immediately.
You will still need (these were fixed in 5.4)
<?php, however, and it will still immediately die on syntax errors, so
I suggest you to use a text editor instead – write some code, save it to
test.php, then run
php test.php from command line. Edit, fix bugs, run
php test.php again.