Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com X-Authentication-Warning: slinky.cs.nyu.edu: pechtcha owned process doing -bs Date: Sun, 4 Apr 2004 15:16:57 -0400 (EDT) From: Igor Pechtchanski Reply-To: cygwin@cygwin.com To: David Fritz cc: cygwin@cygwin.com Subject: Re: Bogus assumption prevents d2u/u2d/conv/etal working on mixed files. In-Reply-To: <406F92EC.707@att.net> Message-ID: References: <406E4184.30904@cwilson.fastmail.fm> <406F92EC.707@att.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Scanned-By: MIMEDefang 2.39 On Sat, 3 Apr 2004, David Fritz wrote: > Charles Wilson wrote: > [...] > > (2) it's an attempt to prevent users from permanently scrogging binary > > files. See: d2u, on a binary file, is an irreversible operation. So, > > if you do "d2u *" you'll probably kill something deep inside some binary > > file, and you can't fix it -- unless some minimal safeguards are in place. > > > > u2d MAY be reversible -- IF there were no pre-exising \r\n > > combinations in the file to begin with -- so when (OMG-fixit-)d2u is > > run, obviously the first '\n' is preceeded by a (newly-added) '\r\n', so > > the prog merrily replaces ALL '\r\n' with '\n'...which MAY fix your > > oops, but maybe not. > > > > > > So, with the current code, if you snarf the first "line" -- all chars > > until the first '\n' -- if it's a binary file the odds are pretty low > > that the immediately-preceeding character is a '\r' -- so d2u as > > currently coded will bail out, and no harm is done. > > > > It doesn't work so well in the other direction -- by the same logic > > above, you'll almost never bail out early if you run 'u2d' on a binary > > file -- but if you immediately do a 'd2u' you MIGHT be able to recover.) > > > [...] > > If detection of binary files is desirable, why not use an explicit test > with a more robust methodology? GNU grep detects binary files by > looking for a '\0' byte. Such a test could be used by both d2u and u2d; > they could bail out with a message like "skipping binary file". > > Cheers Why not just call "file"? ...Before using d2u/u2d? And then call "d2u/u2d --force". Igor -- http://cs.nyu.edu/~pechtcha/ |\ _,,,---,,_ pechtcha@cs.nyu.edu ZZZzz /,`.-'`' -. ;-;;,_ igor@watson.ibm.com |,4- ) )-,_. ,\ ( `'-' Igor Pechtchanski, Ph.D. '---''(_/--' `-'\_) fL a.k.a JaguaR-R-R-r-r-r-.-.-. Meow! "I have since come to realize that being between your mentor and his route to the bathroom is a major career booster." -- Patrick Naughton -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/