Notes:
!UNIX command on the NUUPJB JCL screen, which simply runs a Unix command or shell script after doing MPE-style variable substitution e.g.:
10 !UNIX ud_pg "!GLJ3"
which calls this script named ud_pg:
#!/bin/ksh
clear
pathname=`mapname "$1"`
pg -frs -p ' -- pg command (type "h" for help): ' "$pathname"
It clears the screen, runs the Bi-Tech "mapname" utility to convert the filename from the MPE-style xxx.DATA.ADMIN format to a Unix pathname, assigning the result to the Unix shell variable "pathname", then runs the Unix "pg" utility to page through the file, displaying a helpful prompt and preventing the user from escaping from "pg" to a shell prompt. (thanks to Frank Beitel for this example)