shell editor

[Linux for blind general discussion]

Potential problem with dd is it requires an input file and the first 
creation of the file will be an append operation.  I'll try using 
/dev/null for input and converting all output to spaces when this one 
gets created and it's possible this will work.

On Tue, 26 Sep 2017, Linux for blind general discussion wrote:

> Date: Tue, 26 Sep 2017 07:01:52
> From: Linux for blind general discussion <blinux-list at redhat.com>
> To: Linux for blind general discussion <blinux-list at redhat.com>
> Subject: Re: shell editor
> 
> Thanks, those binary zeros in that context could cause a real mess.
> On Tue, 26 Sep 2017, Linux for blind general discussion wrote:
>
>> Date: Tue, 26 Sep 2017 00:10:43
>> From: Linux for blind general discussion <blinux-list at redhat.com>
>> To: Linux for blind general discussion <blinux-list at redhat.com>
>> Subject: Re: shell editor
>> 
>> The truncate command will likely have an undesired side-effect: if the
>> file is smaller than the target size, it will be generally be padded with
>> binary zeroes to force it to be the specified size.
>> 
>> If pure truncation is desired, might I suggest the dd command instead:
>>  dd if=input-file of=output-file bs=maxlength count=1
>> If the input-file is shorter than maxlength, output-file will be the
>> same as input-file (not padded to maxlength).
>> (warning: maxlength has a limit, but that limit is usually at least 100 
>> Meg.)
>> 
>> On Mon, Sep 25, 2017 at 18:07:24PM -0400, Linux for blind general 
>> discussion wrote:
>>> This isn't what was requested, but I'm pretty certain it will be useful
>>> nonetheless.  The truncate command can create a file and make it a
>>> specific number of characters in size.  Truncation happens from the end of
>>> the file if too large.  So truncate 10000 file.txt would make a file 10000
>>> characters in length.  Editing that file in overwrite mode not insert mode
>>> change lines don't insert lines would use up the space for the character
>>> limit on the file.  Saving an edit; then truncating the file again but to
>>> a different file name than the original then comm -2 file1 file2 would
>>> show lines only in file2 not in file1.
>> 
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