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From: jimb@amdcad.UUCP (Jim Budler)
Newsgroups: net.micro.mac
Subject: Re: Red Ryder Kermit mode problem explained w/workaround
Message-ID: <12847@amdcad.UUCP>
Date: Wed, 27-Aug-86 02:11:36 EDT
Article-I.D.: amdcad.12847
Posted: Wed Aug 27 02:11:36 1986
Date-Received: Wed, 27-Aug-86 11:57:13 EDT
References: <1197@umd5>
Reply-To: jimb@amdcad.UUCP (Jim Budler)
Organization: AMD, Sunnyvale, California
Lines: 87
Keywords: Kermit RedRyder workaround

In article <1197@umd5> zben@umd5 (Ben Cranston) writes:
>It appears that the conflict between Red Ryder's "Kermit mode" and various
>mainframe Kermit programs is due to Red Ryder's implementation of only the
>so-called "image mode" of Kermit, and not the "text mode".
>
>The differance is that "image mode" transfer is strictly byte-for-byte,
>while "text mode" attempts to translate the computers' various "newline"
>schemes to a machine independant end-of-line representation on the wire.
>
>The conflict comes about because Unix uses LF (Linefeed) as a NewLine
>mark while the Macintosh uses CR (Carriage Return), and is complicated 
>by the interactions that take place when one Kermit is in text mode
>and the other is in image mode.
>
>
>Fortunately there is a work-around.  Before downloading a text file from
>Unix to the Macintosh, pass the file through the filter:
>
>    tr '\012' '\015'
>
>which translates the LF codes to CR.  Then, use the image mode on the 
>Unix version of Kermit:
>
>    % kermit -is <thing>
>
>and the file should end up with the proper EOL codes on the Macintosh.
>
>A similar technique can be done when uploading.  Upload the file with
>the image mode set on the Unix Kermit:
>
>    % kermit -ir
>
>then pass it through the filter:
>
>    tr '\015' '\012'
>
>to translate the CR codes to LF to make it a kosher Unix text file.
>
>Be *SURE* to use the image mode on the Unix Kermit:  
>
>If you do not use "image mode" when uploading:
>
>The Unix Kermit will be looking for machine-independant CR-LF pairs for
>newlines, and will actually EAT the bare CR codes the Mac is sending,
>and you will end up with a Unix file with no newlines at all.  It is 
>not possible to recover from this, as the positions of the newlines will 
>have been lost forever.
>
>If you do not use "image mode" when downloading:
>
>The Unix Kermit will send CF-LF pairs for newlines, the Mac will interpret
>the CR as a newline, and the LF codes will appear as square boxes at the
>beginning of each line.  Note that use of the "discard control characters"
>option on Red Ryder will probably get rid of these boxes, but will also
>get rid of any other control characters in the text.
>
>These shell scripts embody the 'tr' calls documented above, and allow an
>optional filename as argument.  They have been tested on Berkeley systems.
>...
>Testing on SVR2, extension to multiple arguments, and other forms of the
>dreaded "feeping creaturism" are left as exercises for the student...

I guess I'm guilty of 'feeping creauturism'.
I do it this way, not for Red Ryder kermit, but for vanilla xmodem
transfer:

With csh:

alias lfcr 'tr "\012" "\015" < \!:1 > \!:2'
alias crlf 'tr "\015" "\012" < \!:1 > \!:2'

Use as follows:

% lfcr inputfile outpufile
% crlf inputfile outpufile

I wont pretend to guess which is better. Mine works, I'm sure his works.
I'm just presenting an alternative. The article was very well written
and informative. Thank You.
-- 
 Jim Budler
 Advanced Micro Devices, Inc.
 (408) 749-5806
 Usenet: {ucbvax,decwrl,ihnp4,allegra,intelca}!amdcad!jimb
 Compuserve:	72415,1200

Once and for all: I like my Macintosh