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I use the following short perl script to shuffle the lines in a file (to produce lists of random strings for testing):
#!/usr/bin/perl -w use strict; open(IN, "<".$ARGV[0]); my @lines = <IN>; close(IN); shuffle(\@lines); print $_ foreach (@lines); sub shuffle { my $array = shift; my $i = $#{$array}+1; while ($i != -1) { $i--; my $j = int rand ($i+1); next if $i==$j; @$array[$i,$j]=@$array[$j,$i]; } }
When I run this on a 70mb file, ~11 million lines, this eats about 1.5 gigs of ram (all I have left) then hits "Out of Memory!" before it's finished reading the file.

I have swap disabled, I suppose that would allow me to run this. However, I'm curious -- why does it need so much memory to store 70mb of data? Is there anything I can do here? I tried presizing the array to 12 million, that did not make any difference (can I presize each element, eg, request a block of a given size?).

In reply to mem usage by halfcountplus

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