Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!mks!tj
From: tj@mks.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: command.com redirection quoting (WAS: stupid COMMAND.COM)
Message-ID: <229@mks.UUCP>
Date: Fri, 13-Mar-87 14:36:49 EST
Article-I.D.: mks.229
Posted: Fri Mar 13 14:36:49 1987
Date-Received: Sat, 14-Mar-87 06:01:59 EST
References: <2091@ncoast.UUCP> <409500003@prism> <2986@iuvax.UUCP> <2438@dalcs.UUCP>
Organization: Mortice Kern Systems, Waterloo, Ont.
Lines: 23
Keywords: DOS command.com redirection quoting
Summary: command.com does redirection and sloppy quoting

In article <2438@dalcs.UUCP>, dalegass@dalcs.UUCP (Dale Gass) writes:
> When DOS gives control to a .com or .exe file, it simply passes the whole
> command line to it, and let's it do what it wishes with the info.
> I think, however, that piping '|' *is* intercepted at the DOS level,
> whereas the '>' and '<' redirections are not.

DOS 2.0 through 3.2 have command.com doing redirection and piping, using
`<' `>' `|', which therefore do not appear in the command tail.

However, quoting (with `"') is supported to get these characters to appear
in the command tail, but the `"'s are NOT stripped. This is not particularly
useful to programs using the command tail directly, but most C compilers use
runtime startup code for preparing (argc, argv) for main() which strip quotes
as a side effect (allowing args with embedded ` 's, for example).
There are even startups with relic code (from DOS 1?) for doing redirection.
If your own program chokes on `"|"' before reaching main(), suspect the startup
of excessive ambition. In my experience Mark Williams, Microsoft, and Wizard
do not have any problem with quoted [<>|].
-- 
     ll  // // ,~/~~\'   T. J. Thompson {decvax,ihnp4,seismo}!watmath!mks!tj
    /ll/// //l' `\\\     Mortice Kern Systems Inc.
   / l //_// ll\___/     43 Bridgeport Rd. E., Waterloo, ON, Can. N2J 2J4
O_/                      (519)884-2251