Re: PROMPT_COMMAND='history -a; history -n' causes shell hang in OX 10.10 Yosemite / bash 3.2.53

[Chet Ramey]

On 11/6/14, 5:19 AM, Piotr Grzybowski wrote:
> On Thu, Nov 6, 2014 at 3:28 AM, Chet Ramey <chet.ramey@case.edu> wrote:
>>
>> In theory, one could change the functions in history.c and histfile.c to
>> change the in-memory history list to one that uses a file, possibly with
>> mmap().
>> I'd be happy to look at contributed code to do this [..]
> 
>  would you accept a solution like this:
> 
> 1. all running instances of bash with history support on, share
> history via shmem segment (some care as to its size should be taken)
> 2. $HISTFILE in every bash points to history file where every bash
> writes history in chronological (depending on settings) order

You could use mmap, but the synchronization between different shells
writing to the same mmaped segment is a problem that has to be solved.

> 3. $HISTFILE is only read on startup, if there are no other bash
> instances running
> 4. sharing of history and synchronisation between instances is
> realised via standard ipc

There is no "standard ipc" except pipes across the range of systems bash
runs on.


-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/