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Re: redirect-append (>>) creates garbage-y file


On 09.03.2010 20:41, William Lebow wrote:
I've diagnosed this problem further. It is an interaction between cygwin and a security package called "Credant Guardian Shield" that my company installs on all of its laptops. I can't say specifically that it is a cygwin bug, but this bad behavior is not present in earlier versions.

As described below, the problem is a command like "echo foo>> foo.txt" creates a file that starts with a bunch of garbage, and ends with the expected text.
It would be interesting to check whether it only occurs if you append to a file from the command line or also if an application opens a file in append mode,
in which case the issue would be much more critical I think.
In any case, I would also submit a bug report to that security package.
------
Thomas
-- Bill



-----Original Message-----
From: William Lebow [mailto:William.Lebow@phaseforward.com]
Sent: Sunday, March 07, 2010 2:58 PM
To: cygwin@cygwin.com
Cc: blebow@alum.mit.edu
Subject: redirect-append (>>) creates garbage-y file

I'm a long time cygwin user, but I am having the weirdest problem after installing on my new Dell laptop running Windows XP professional. I'd be grateful for any advice or hints from this group.

I am doing a simple redirect-append (>>, that is) to create a new file. When I do this the new file has twice as many characters as I expect and the first bunch of characters are seemingly garbage.

This only happens with ">>" and only if I am creating a new file.
Using ">>" to append to a file is no problem.
Using ">" to create a new file is not problem

So far this has not been reproducable on any other PC.

I am using the bash version 3.2.49(23)-release (i686-pc-wygwin) , with the 1007.1.0.0 cygwin1 dll-- see attached output from cygcheck.

Some examples follow::

#################################
#### Example 1
#### I expect 4 characters (including the terminator); I get 7 #### The first 3 characters are unwanted
   $ echo abc>>  test1.txt
   $ wc test1.txt
   1 1 7 test1.txt
   $ cat test1.txt
   0▒▒abc

$ hexedit test1.txt
00000000   30 B5 A2 61  62 63 0A                                            0..abc.

#################################
#### Example 2
#### I expect 8 characters (including the terminator); I get 15 #### The first 7 characters are unwanted
   $ echo abcdefg>>  test2.txt
   $ wc test2.txt
    1  1 15 test2.txt
   $ cat test2.txt
   ▒▒\zB▒▒abcdefg

hexedit test2.txt
00000000   AD EB 5C 7A  42 B6 C5 61  62 63 64 65  66 67 0A                  ..\zB..abcdefg.


################################# #### Example 3 #### Use> instead of>> and I get exactly what I should get $ echo abc> test3.txt $ wc test3.txt 1 1 4 test3.txt $ cat test3.txt abc



Many thanks for any help

-- Bill

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