$ perldoc perlfunc | grep FILENAME | egrep '^ *[a-z]+ [A-Z]'
       chroot FILENAME
       mkdir FILENAME,MASK
       mkdir FILENAME
       rmdir FILENAME
       sysopen FILEHANDLE,FILENAME,MODE
       sysopen FILEHANDLE,FILENAME,MODE,PERMS
 $ say 'map prototype("CORE::$_"), qw/ chroot mkdir rmdir sysopen /'
_
_;$
_
*$$;$