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From: toma@tekgvs.LABS.TEK.COM (Tom Almy)
Newsgroups: comp.sys.ibm.pc
Subject: Re: append " >> " is not working, why?
Message-ID: <5940@tekgvs.LABS.TEK.COM>
Date: 15 Sep 89 14:47:39 GMT
References: <4734@shlump.nac.dec.com> <2553@pur-phy>
Reply-To: toma@tekgvs.LABS.TEK.COM (Tom Almy)
Organization: Tektronix, Inc., Beaverton,  OR.
Lines: 28

In article <2553@pur-phy> qz@maxwell.physics.purdue.edu.UUCP (Qin Zhao) writes:
>  Hi, I recently got some problem when I tried to concatenate two files.
>What I have done is following:
>  There is tow file: file1 and file2 ( I got from somebody else ).
>  I gave command:
>		 type file2 >> file1
> in order to put file2 at the end of file1.  And then I used "dir" to check 
>the size of file1, it was increased by the  size of file2.
>However, when I tried to read the contents of file1, I could only see the 
>original part of file1. I had used several editors, and "type" commands. 
>But when I rewrote  file1 using the editor, the size of file1 drops to the 
>original size of file1.

While DOS is perfectly capable of knowing file sizes, DOS was originally 
designed as a copy of CP/M, which had fixed length (128 byte) blocks.  In
CP/M you would mark the end of an ASCII file with a control-Z character.
Because of this, most DOS programs that handle text treat a control-Z
character as an end-of-file marker.

File1 was undoubtedly created by a program that inserts control-Zs at the
end of file (typical for programs that trace their roots back to CP/M).  
So when you append file2 to the end of file1, file1 has a control-Z character
at the end of its original data.  The editors and type commands you used
simply stopped at the control-Z.

Tom Almy
toma@tekgvs.labs.tek.com
Standard Disclaimers Apply