These five lines were whipped up to sort a massive file on a date field styled MM/DD/YY. It's based on a cross between a GRT and ST, with my own little enhancement. Rather than loading the entire file into memory and then taking references to in-memory elements, the program records in-file positions, and then prints out the file as read at those locations.

Hope you find it useful,
-v

Update: jdporter reminded me it's "GRT" not "GSR". Thanks!

# An evil collection of one-liners to make this five-line
# script which sorts a file by a date field.  It's designed
# for massive files, and indexes directly into the file.

open(FD,"data") || die;

my ($loc,@a) = (tell(FD));

push(@a,[$loc,(split /\|/)[4]]),$loc = tell(FD) while(<FD>); # 4 is th
+e datefield

seek(FD,$_,0), $_ = <FD>,
  print for map { $_->[0] }
            sort { $a->[1] cmp $b->[1] }
            map { [$_->[0],
                  sprintf "%04d%02d%02d",(split /\//,$_->[1])[2,0,1]] 
+} @a;

close FD;

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In reply to Sort Large Files by Velaki

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