Re: bash oom problem

On 04/10/09 15:28, Mikkel wrote:

Patrick O'Callaghan wrote:

On Sun, 2009-10-04 at 13:54 +0100, psmith wrote:

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

As Sam says, your initial attempt is trying to produce all 1.5TB at
once, which is why it blows up, but that's going to happen anyway even
if you program the same thing in C. IOW it's not an issue with the Shell
per se, but with the approach to the problem.

Assuming you actually want all 1.5TB of data (really?) you'd be better
consuming it as it's produced, perhaps via a pipe. Of course that
depends on what you're doing with it, which you haven't said.

poc

One way to do it would be to break it down into nested loops. I am
not sure you could do it in bash - I am not sure how bash handles
loops. You can try something like: (Not tested)

for a in {A..Z}; \
do for b in {A..Z}; \
do for c in {A..Z}; \
do for d in {A..Z}; \
do for e in {A..Z}; \
do for f in {A..Z}; \
echo $a$b$c$d$e$f ; \
done ; done ; done ; done ; done ; done ; done ; done

Mikkel

for a in {A..Z}; \
do for b in {A..Z}; \
do for c in {A..Z}; \
do for d in {A..Z}; \
do for e in {A..Z}; \
do for f in {A..Z}; \
do for g in {A..Z}; \
do for h in {A..Z}; \
do echo $a$b$c$d$e$f$g$h; \
done;done;done;done;done;done;done;done; > wl1

thanks again
phil

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