If a procedure expects input on stdin, you can still drive it from a shell script or batch command by redirecting a prepared input file.

; intest.pro
pro intest
   read, one
   read, two
   a = ' '
   read, a
   read, realnum
   print, one, two, ' ', a, realnum
end

; callintest.pro
intest
exit

idl callintest < input.dat

For shell-based automation that needs argument passing rather than stdin redirection, the PPPL workflow also used helper wrappers such as idlbatch.pl.