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From: hes@ecsvax.UUCP (Henry Schaffer)
Newsgroups: net.micro.pc
Subject: Appending to files. (pc-dos, ms-dos)
Message-ID: <900@ecsvax.UUCP>
Date: Thu, 12-Dec-85 20:59:24 EST
Article-I.D.: ecsvax.900
Posted: Thu Dec 12 20:59:24 1985
Date-Received: Sat, 14-Dec-85 08:10:14 EST
Distribution: net
Organization: NC State Univ.
Lines: 45

<>In unix one can redirect output to a file using  >  or redirect
output to append to an existing file using  >>  .
E.g., assuming that file "test" has some text in it:

   cat test >  test2
   cat test >> test2

produces two sequential copies of the test file in the test2 file.
This can be verified by looking at test2, e.g., by  cat test2.
So I tried to do the same thing in pc-dos 2.10.  (I'm guessing that 
the same thing will happen in ms-dos - correct me if I'm wrong.)

   type test >  test2
   type test >> test2

test2 ends up the correct size (in the dir listing), but type test2
only gives *one* copy of test.  A quick list using debug shows that
appending leaves the end-of-file-marker (^Z, hex 1A) in place and
appends after it.  So "type" stops at the first EOF and doesn't ever
show the second copy of "test".

The manual (Chap. 1, p. 6) simply says that the >>  "Causes filename
to be opened (created if necessary) and positions the write pointer
at the end of the file so that all output is appended to the file."

It is possible to append files, omitting the intermediate EOFs, by
using the concatenate option of the COPY command.  Thus one can 
always pipe to a new file, and then append that file as desired by
using COPY.  However that is an extra step - and it looks as if the
>> is pretty much useless.

Is there some way to use the >> in the same manner as in unix?
Is this a peculiarity of pc-dos vs. ms-dos?  Any sage words of
wisdom would be welcome.

--henry schaffer

P.S. In case anyone is wondering why I care - I just got a copy of
the ms-dos version of UNIX|STAT 5.1, which is a very good package
of statistically oriented unix-style programs.  I'm trying to learn
how to use it effectively, and so I am using i/o redirection and 
pipes.  After seeing how nicely these techniques do work (they do
work even on a floppy diskette system, but much more nicely on a
hard disk system) I've decided that most programs for ms-dos/pc-dos
are really cp/m-style rather than unix-style.