Writing to /dev/clipboard from multiple processes in Bash gives inconsistent behaviour
Andrey Repin
anrdaemon@yandex.ru
Thu Feb 12 22:50:00 GMT 2015
Greetings, Corinna Vinschen!
> On Feb 12 13:45, Adam Dinwoodie wrote:
>> I've spotted some slightly odd behaviour when writing things from
>> multiple processes to /dev/clipboard.
>>
>> Easiest to show this with an example:
>>
>> for n in {1..10}; do echo $n; done >/dev/clipboard; cat /dev/clipboard
>>
>> I expect this to print out the numbers 1–10 to the terminal. Sometimes
>> it does, but sometimes it misses out some of the numbers at the end;
>> printing the digits 1–8, say, but no more. Generally it gets to around
>> 7–9, but I've seen it managing to only get up to 3 on one occasion.
> I can't reproduce this. First I tried this manually a couple of times,
> but then I created a loop:
> for i in {1..1000}
> do
> echo > /dev/clipboard
> for n in {1..10}; do echo $n; done > /dev/clipboard
> grep -q 10 /dev/clipboard || cat /dev/clipboard
> done
> and it didn't fail once. I'm not sure what to do if I don't have a
> reproducible testcase...
Failed ~20 times for me. And the more, the more I run the test.
What is more curious, is if I modify your test to only print "1",
while true; do
echo > /dev/clipboard
for n in {1..10}; do echo $n; done > /dev/clipboard
grep -q 10 /dev/clipboard || grep 1 /dev/clipboard
done
it sporadically print 10 !
And my mail client actively flashing "paste" buttons, when the script is
working in background. May be that's it.
This is more visible:
$ while true; do { i=$(( $i+1 )); echo > /dev/clipboard; for n in {1..10}; do echo $n; done > /dev/clipboard; grep -q 10 /dev/clipboard || { grep 10 /dev/clipboard && echo $i;};}; done;
10
3512
10
6543
10
9468
10
9936
10
12298
--
WBR,
Andrey Repin (anrdaemon@yandex.ru) 12.02.2015, <23:56>
Sorry for my terrible english...
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