Re: minicom questions, need expert

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On Monday 12 May 2008, Kevin J. Cummings wrote:
>Gene Heskett wrote:
>--
>Kevin J. Cummings
>kjchome@xxxxxxx
>cummings@xxxxxxxxxxxxxxxxxx
>cummings@xxxxxxxxxxxxxxxxxxxxxxx
>Registered Linux User #1232 (http://counter.li.org)
>
>> On Monday 12 May 2008, Mikkel L. Ellertson wrote:
>>> Gene Heskett wrote:
>>>> But, this command line, which outputs to the screen very nicely if the
>>>> pipe and the rest of the line are removed, seems to send the data to
>>>> /dev/null:
>>>>
>>>> #>cat /dev/ttyUSB1 | lpr -Plp1
>>>
>>> Try something like:
>>> cat /dev/ttyUSB1 | lpr -Plp1 -
>>> or
>>> cat /dev/ttyUSB1 | lpr -Plp1 -- -
>>
>> Either of those give this:
>> [root@coyote ~]# cat /dev/ttyUSB1 | lpr -Plp1 -
>> lpr: Error - unknown option '
>> ^C
>> [root@coyote ~]# cat /dev/ttyUSB1 | lpr -Plp1 -- -
>> lpr: Error - unknown option '-'!
>>
>> Thanks.
>>
>>> From the lp man page:
>>> lp submits files for printing or alters a pending job. Use a
>>> filename of "-" to force printing from the standard input.
>
> From the lpr man page:
>>        lpr submits files for printing. Files named on the command line are
>> sent to the named printer (or the system default destination if  no
>> destination is specified). If no files are listed on the command-line, lpr
>> reads the print file from the standard input.
>
>So:
>
>cat /dev/ttyUSB1 | lpr -Plp1
>
>should be all that's needed....

sorry about the late rely here Kevin.  The above example, except to -Plp3, has 
been running for about 4 hours, and I have sent 11 copies of that directory 
listing up the /dev/ttyUSB1 cable now with nothing going to that printer, or 
when changed to lp1 which is right beside me.  Neither that, nor a

cat /dev/ttyUSB1 | lp -d lp3 -

works, both apparently doing exactly the same thing with the data, stuffing it 
into a file in /tmp, which is not printed, and which is deleted if I ctl-c 
the command line.

That has resulted in some activity I can see with htop, for both cat and lpr, 
and there is now a file of some 105k in /tmp that contains these directory 
listings.  The tail end of this /tmp/file looks like this in text format:

[root@coyote tmp]# tail 482b58beea317
   0  2008/05/13 21:00  --e-rewr    6B08      1B01 ed
   0  2006/04/21 13:38  --e-rewr   1EF6C       16C wcreate
   0  2006/04/21 13:38  --e-rewr   1EF70       439 xmode
   0  2008/05/12 13:05  ------wr    BFF4       211 GSort
   0  2008/05/13 21:54  --e-rewr    3FF0       4EA noautoex
   0  2008/05/13 21:09  --e-rewr    FEDC       4EA multivue
   0  1995/04/30 16:30  ----rewr    FFF8      39BF GShell
   0  1987/09/29 19:27  --e-rewr   1ECAC      3A6E Control
   0  1988/02/19 20:02  --e-rewr   1ECB4       1DE compare

And in hexdump -C format:

00003c20  38 20 20 20 20 20 20 33  39 42 46 20 47 53 68 65  |8      39BF GShe|
00003c30  6c 6c 0a 20 20 20 30 20  20 31 39 38 37 2f 30 39  |ll.   0  1987/09|
00003c40  2f 32 39 20 31 39 3a 32  37 20 20 2d 2d 65 2d 72  |/29 19:27  --e-r|
00003c50  65 77 72 20 20 20 31 45  43 41 43 20 20 20 20 20  |ewr   1ECAC     |
00003c60  20 33 41 36 45 20 43 6f  6e 74 72 6f 6c 0a 20 20  | 3A6E Control.  |
00003c70  20 30 20 20 31 39 38 38  2f 30 32 2f 31 39 20 32  | 0  1988/02/19 2|
00003c80  30 3a 30 32 20 20 2d 2d  65 2d 72 65 77 72 20 20  |0:02  --e-rewr  |
00003c90  20 31 45 43 42 34 20 20  20 20 20 20 20 31 44 45  | 1ECB4       1DE|
00003ca0  20 63 6f 6d 70 61 72 65  0a 0a 1b                 | compare...|

perhaps there is a clue here, like some control character missing?

As the src machine is not sending \n's, only \r's, /dev/ttyUSB1 is set to 
translate \r's to \n's with stty options.

Does it need an EOF ($1B) to trigger the actual printing?  I'm not sure I can 
make the src machine do that, but I'll try.  Yes, I could, but as a separate 
line of the program and it shows in the above hexdump.  As a test its ok, but 
for day to day operations it would be a dud.

lpr is the owner of this file according to "lsof|grep lpr":
lpr       3533      root    4u      REG        8,3      15531   
82903079 /tmp/482b9fa495624

And just now, switching screens, I locked the machine up tight and had to hit 
the reset button.  6 day uptime for 2.6.26-rc1 wrecked.

Perhaps the trigger for lpr to actually print it is some other control 
character?  I'm bumfuzzled to be sure, 2 days of screwing with this.

Many thanks, to Kevin J. Cummings, or anyone else who can shed some light on 
this.

>--
>Kevin J. Cummings
>kjchome@xxxxxxx
>cummings@xxxxxxxxxxxxxxxxxx
>cummings@xxxxxxxxxxxxxxxxxxxxxxx
>Registered Linux User #1232 (http://counter.li.org)

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
The Edsel. New Coke. Windows 2000. All mandatory case studies for bizschool
students in 2020.

   -- Bear Giles (in a LinuxToday post)

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