Re: CR/LF

[Jim Popovitch <jim@k4vqc.com>]

On Sat, 2022-12-10 at 23:44 -0500, Greg Wooledge wrote:
> On Sat, Dec 10, 2022 at 11:16:12PM -0500, Jim Popovitch wrote:
> > On Sat, 2022-12-10 at 22:10 -0500, Greg Wooledge wrote:
> > > On Sat, Dec 10, 2022 at 10:07:48PM -0500, Jim Popovitch wrote:
> 
> > > > > > Why does this produce a CR/LF
> 
> > > There is still no CR.  At all.  Ever.  This is not Microsoft Windows.
> > 
> > Why would you assume Windows is involved?  This is about running cmds
> > from Debian 11 to Debian 11.
> 
> Then there is no CR/LF.  There is only LF.
> 
> > > So... what are you actually trying to do?
> > 
> > Run cmds on a remote system, that is captured locally in a variable,
> > where said cmds may or may not produce output.
> 
> OK.  You have a few choices:
> 
> 1) Throw away the notion that you can store the output in a variable, and
>    store it in a file instead.  This is the simplest and safest thing to
>    do.  If the command produces binary data (including NUL bytes), it's
>    not possible to store it directly in a shell variable.  But it can
>    always be stored in a file.
> 
>    Redirection to a file also dodges all the insane issues of data
>    modification that you get with the other choices.
> 
> 2) Use a command substitution.  This has two issues:
> 
>    a) It cannot handle binary data -- only text.
>    b) All trailing newlines will be stripped by the command substitution.
> 
>    If you're certain the output will be text, but you need to preserve
>    the correct number of newlines in the output, then the standard
>    workaround is to append a fixed character to the stream, and remove
>    it afterward:
> 
>    myvar=$(ssh whatever; printf x)
>    myvar=${myvar%x}
> 
>    That preserves the output stream in its original form.
> 
> 3) Pipe the command through something like base64, and use a command
>    substitution to store the base64 encoded data stream in the shell
>    variable.
> 
>    Then use base64 -d (or whatever inverts your choice of encoding) when
>    you need to use the data.
> 

Thanks, all of that is very informative and certainly nothing like the
rants and ravings of a senile old man. :)


> > Taking $() out of the equation doesn't change the result. The following
> > will add a CR/LF: 
> 
> THERE IS NO CR!
> 
> >   TEST=`ssh -o LogLevel=QUIET -t user@server "echo -n ''"`; echo ${TEST}
> 
> COMMAND SUBSTITUTION REMOVES ALL TRAILING NEWLINES.
> 
> IT DOES NOT MATTER WHETHER YOU USE THE MODERN $() OR THE ANCIENT AND
> DEPRECATED BACKTICKS.
> 
> YOU ARE **STILL** FAILING TO QUOTE CORRECTLY!
> 
> YOU ARE **STILL** USING echo WHICH ADDS A NEWLINE AND THEN WONDERING WHY
> A NEWLINE IS ADDED.
> 
> .... I'm done.  Continuing the self-abuse of attempting to help you
> is going to be pointless, so please read the answers you've already
> been given.  I won't give you any more.
> 

welp.

Hope you have a good day tomorrow,

-Jim P.