From: Brian Inglis <Brian.Inglis@SystematicSw.ab.ca>
To: cygwin@cygwin.com
Subject: Re: Bash shell script issue
Date: Wed, 07 Sep 2016 19:16:00 -0000 [thread overview]
Message-ID: <91b97490-5440-39bd-1940-68994a0ec62a@SystematicSw.ab.ca> (raw)
In-Reply-To: <1709131555.354781.1473264514358@mail.yahoo.com>
On 2016-09-07 10:08, Kipton Moravec wrote:
>> From: Eric Blake
>> On 09/06/2016 05:36 PM, Kipton Moravec wrote:
>>> I this is the script:
>>> #!/bin/bash
>>> echo $PWD
>> Insufficient quoting. This does not do the right thing if $PWD contains
>> spaces. But not necessarily related to your problem at hand.
>>> project_root=$PWD
>>> echo $project_root
>> Again, insufficient quoting.
>>> x=${project_root}/tools
>>> echo $x
>> And again.
>>> echo ${x} | cat -A
>>> On original Windows 7 computer I get:
>>> dalkmora@DALM0048 ~/walnut/dp2b_walnut_customer_flextronics/walnut
>>> $ ./testconvert1.sh
>>> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
>>> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
>>> /toolsdalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
>>> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut^M/tools^M$
>> The carriage returns are likely a product of you editing the file in
>> text mode (Windows notepad is notorious for this, but many other native
>> programs do likewise), but trying to execute the script in binary mode
>> (the default, if you do not use 'set -o igncr').
>>> What am I doing wrong or is this an error?
>>> Where do the carriage returns (^M) come from, and how do I get rid of them?
>> d2u /path/to/your/script
>> to remove all the carriage returns from your careless editing. Once they
>> are gone, then you don't need the 'igncr' crutch to tell bash to go into
>> text mode.
> As I said I am new to shell scripting. I have been programming
>microcontrollers, bare bones with no OS for most of the past 40 years.
> dalkmora@DALM0048 ~/walnut/dp2b_walnut_customer_flextronics/walnut
> $ od -cx testconvert1.sh
> 0000000 # ! / b i n / b a s h \r \n e c h
> 2123 622f 6e69 622f 7361 0d68 650a 6863
> 0000020 o $ P W D \r \n p r o j e c t _
> 206f 5024 4457 0a0d 7270 6a6f 6365 5f74
> 0000040 r o o t = $ P W D \r \n e c h o
> 6f72 746f 243d 5750 0d44 650a 6863 206f
> 0000060 $ p r o j e c t _ r o o t \r \n x
> 7024 6f72 656a 7463 725f 6f6f 0d74 780a
> 0000100 = $ { p r o j e c t _ r o o t }
> 243d 707b 6f72 656a 7463 725f 6f6f 7d74
> 0000120 / t o o l s \r \n e c h o $ x \r
> 742f 6f6f 736c 0a0d 6365 6f68 2420 0d78
> 0000140 \n e c h o $ { x } | c a t
> 650a 6863 206f 7b24 7d78 7c20 6320 7461
> 0000160 - A
> 2d20 0041
> 0000163
> Shows there is not "careless editing".
> So "Insufficient quoting" means nothing to me. How should it be?
>I was taking the example from a shell script I found.
> So I added quoting on the echo:
> #!/bin/bash
> echo "$PWD"
> project_root=$PWD
> echo "$project_root"
> x=${project_root}/tools
> echo "$x"
> echo "${x}" | cat -A
> dalkmora@DALM0048 ~/walnut/dp2b_walnut_customer_flextronics/walnut
> $ ./testconvert1.sh
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /toolsdalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut^M/tools^M$
> No difference.
> So maybe in the commands?
> #!/bin/bash
> echo "$PWD"
> project_root="$PWD"
> echo "$project_root"
> x="${project_root}"/tools
> echo "$x"
> echo "${x}" | cat -A
> dalkmora@DALM0048 ~/walnut/dp2b_walnut_customer_flextronics/walnut
> $ ./testconvert1.sh
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /toolsdalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut^M/tools^M$
> Again no difference.
> So finally I looked up d2u
> dalkmora@DALM0048 ~/walnut/dp2b_walnut_customer_flextronics/walnut
> $ d2u testconvert1.sh
> dos2unix: converting file testconvert1.sh to Unix format...
> dalkmora@DALM0048 ~/walnut/dp2b_walnut_customer_flextronics/walnut
> $ ./testconvert1.sh
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut/tools
> /home/dalkmora/walnut/dp2b_walnut_customer_flextronics/walnut/tools$
> That fixed it, but I still do not understand it.
> Why are there ^M (carriage return) in the middle of a line?
>I can understand the confusion at the end of the line.
>But there was none shown in the middle from od command.
od does not dump lines, it dumps blocks of bytes, 16 per line in the above
case, and there every \n <NL/LF/^J/ctrl-J> is preceded by \r <CR/^M/ctrl-M>:
TTY line terminators, used by Windows; Unix, Cygwin, and OS X Darwin use
Multics line terminators \n <NL/LF/^J/ctrl-J>; native Mac OS X apps use \r
<CR/^M/ctrl-M> like Apple I.
If you have to use od, try od -Ax -tx1z ... for split hex/text output, or
install xxd hexdump utility from Cygwin packages (part of vim, but packaged
separately), and use xxd -g1 ...
[really: octal dump, and short words; how many decades has it been since
anyone used non-binary-multiple bytes? I know RMS (and I) grew up using
octal and 6, 7, and 9 bit characters, but seriously time to let go... ;^> ]
Googling 'notepad++ Unix format', summarizing boxed first hit:
Edit > EOL Conversion > Unix Format.
Googling 'notepad++ hex view' displays:
View > Show Symbols > Show all characters.
Finally, go native - install and learn emacs or vim - but never ask which! ;^>
--
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada
--
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next prev parent reply other threads:[~2016-09-07 19:16 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <330568691.2384551.1473201409220.ref@mail.yahoo.com>
2016-09-06 22:39 ` Kipton Moravec
2016-09-07 1:21 ` Eric Blake
2016-09-07 1:41 ` Michel LaBarre
2016-09-07 15:35 ` Kipton Moravec
2016-09-07 15:49 ` Marco Atzeri
2016-09-07 17:41 ` Erik Soderquist
2016-09-07 16:05 ` Andrey Repin
2016-09-07 16:25 ` Kipton Moravec
2016-09-07 16:22 ` Kipton Moravec
2016-09-07 17:35 ` Andrey Repin
2016-09-07 18:09 ` Eliot Moss
2016-09-07 18:28 ` Eric Blake
2016-09-09 19:37 ` Gene Pavlovsky
2016-09-07 19:16 ` Brian Inglis [this message]
[not found] ` <32e004cb44addbaefde0839df5500d60@www.ds.net>
[not found] ` <039bcc69d005bf6db5aba99a90f51e36@www.ds.net>
2016-09-07 17:54 ` wilson
2016-09-07 18:13 ` Eliot Moss
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