wayne@teemc.UUCP (//ichael R. //ayne) (02/02/90)
In article <299.25C6D7AD@weyr.FIDONET.ORG> Jim.Gilliland@p3.f209.n141.z1.FIDONET.ORG (Jim Gilliland) writes: (in response to my request for info on redirecting CMD) > >CMD.EXE can be redirected to use a COM port for its STDIN, STDOUT and STDERR, >but its behavior in this situation may be confusing, especially with respect >to STDIN. When CMD.EXE discovers that its STDIN has been redirected, it makes >a couple of changes in its input handling. First of all, it does not echo its >input. Second, it ignores Carriage Returns (0x0D), and honors only Line Feeds >(0x0A) as line terminators. So it may well appear that it is not responding >to input - since you can't see what you type and when you press Enter, nothing >happens! So perhaps you have been successful without realizing it. It's easy >to find out - just press Ctrl-J at the end of the line instead of Enter. Well, there are still a few "problems": 1) <bs> doesn't eliminate the characters. 2) <lf> does indeed terminate lines but does not generate a corresponding <CR> (This is an annoyance more than totally devastating). 3) There does not appear to be a way to enter <EOF>. ^Z does not seem to do anything. 4) There is no way to interrupt a process. ^C does not have any effect. 5) Shutdown doesn't shutdown the detached process!!!!! 6) We tried some simple commands with devastating results. As an example, putting a disk into the A: drive and typing diskcopy A: A: generated an infinite number of error messages interleaved with the same number of prompts to insert the disk. I was never prompted for input though (not even the first time). So, is it really hopeless to do anything from the COM port or does it just look that way? /\/\ \/\/ -- Michael R. Wayne --- TMC & Associates --- wayne@teemc.uucp INTERNET: wayne%teemc.uucp@sharkey.cc.umich.edu uunet!edsews!teemc!wayne Operator of the only 240 Horsepower UNIX machine in Michigan