$ if (p1 .nes. "") then goto file_given
$ type sys$input

Usage:   screenview file [first_page max_pages magnification]

$ exit
$
$ file_given:
$ open/write temp sys$scratch:crude.tmp
$ write temp p1
$ write temp p2
$ write temp p3
$ write temp p4
$ close temp
$ on warning then goto finish
$ define/user sys$input sys$scratch:crude.tmp
$ r TeX_Root:[Drivers.Screenview]Crudetype
$
$ finish:
$ delete/nolog sys$scratch:crude.tmp;
$ exit