bash oom problem

psmith psmith at fedoraproject.org
Sun Oct 4 12:54:49 UTC 2009


On 04/10/09 11:17, Sharpe, Sam J wrote:
> 2009/10/4 psmith<psmith at fedoraproject.org>:
>    
>> hi list, whilst trying to run this bash command
>>
>> for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo $w;done>
>> wl1
>>      
> Consider that for a second...
>
> You are trying to generate a list of all possible combinations of an 8
> character word composed of only uppercase letters - that's 26^8
> combinations (208 Billion). Each word is 8 bytes long, which I make to
> be 1670616516608 bytes... or to put it another way, 1.5 TB
>
> So, you've got 4 GB of virtual memory and you are trying to fit an
> 1555GB array into it. Simple mathematics says no. Dumping the
> arguments before it dies is pointless, because it hasn't even got as
> far as expanding arguments yet.
>
> You need to think of another was to do this and I humbly suggest that
> Bash should not be high on your list.
>
>    
thanks for the reality check sam :o

do you have any suggestions what/where i should be looking to get my 
required output?

phil




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