It seemed kind of obvious to me even at that time that it was taken from Perl. I just didn't get why. PHP could have lifted IMPLEMENTATION DIVISION from COBOL, but likewise, there would have been no point either (fortunately it didn't do that!).
Early web was written in Perl, I guess it was the classic approach of lets borrow what is already successful and in end PHP won over Perl so it worked too. Bill Gates would have been proud.