Re: `printf -v foo ""` does not set foo=
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On 6/24/13 6:52 PM, Mike Frysinger wrote:
> On Monday 24 June 2013 16:13:01 Chet Ramey wrote:
>> On 6/17/13 1:27 AM, Mike Frysinger wrote:
>>> simple test code:
>>> unset foo
>>> printf -v foo ""
>>> echo ${foo+set}
>>>
>>> that does not display "set". seems to have been this way since the
>>> feature was added in bash-3.1.
>>
>> printf returns immediately if the format string is null. It has always
>> been implemented this way.
>
> seems like when the -v arg is in use, that [otherwise reasonable] shortcut
> should be not taken ?
Maybe. I'll take a look. I suspect that the amount of code that depends
on the current behavior is pretty small.
Chet
- --
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRUc...@case.eduhttp://cnswww.cns.cwru.edu/~chet/
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Re: corrupted input after size function (input that's not recorded by bash)
On 6/13/13 3:58 PM, Linda Walsh wrote:
>
> I have a small function in my bashrc:
>
> function showsize () {\
> local s=$(stty size); local o="(${s% *}x${s#* })"; s="${#o}";\
> echo -n $o; while ((s-- > 0));do echo -ne "\b"; done; \
> }
> export -f showsize
> trap showsize SIGWINCH
> ---
> That has the effect of showing me my current window size
> when I resize it.
>
> The odd thing is, if I use it while at a bash input prompt --
> any command I type has the first word ignored.
I haven't looked closely at this yet, but I bet that bash-4.2 running the
trap immediately when the SIGWINCH is received is screwing up the parser
state. A quick test shows me that running this on an empty line, then
hitting return after resizing the terminal and before entering a new
command, does not result in any errors.
This won't work in bash-4.3, which runs traps at command boundaries to
avoid just this kind of corruption.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRUc...@case.eduhttp://cnswww.cns.cwru.edu/~chet/
Re: How to test if a link exists
Dave & John, thank you both. I think you are both right that my solution is [ -a file -o -h file ] || echo "ok to create file" However I personally feel that there ought be a simple test for this situation, there are still a few spare letters that could be used for the test ;) I'm willing to bet there is plenty of code out there that tries to decide whether it is safe to create a file and would fall foul of an errant dead symbolic link. A little off topic but are -a and -e identical? Cheers, mark
