I think it is called "Schwartzian Transform". That's why you couldn't find it ;-). Basically it's a sorting technique for arrays of multiple fields. With it you can sort them according to any fields you prefer. Suppose you have this data:

-r--r--r--   1 yourname       8318 Jan 30  1996 file1.txt
-r--r--r--   1 yourname      11986 Jan 30  1996 file2.txt
-r--r--r--   1 yourname      46852 Feb 27  1996 file3.txt
-r--r--r--   1 yourname      72698 Feb 27  1996 file4.txt
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And you want to sort them according to size. You would do it with ST like this:

@sorted_by_size = 
  map { $_->[0] } 
  sort { $a->[1] <=> $b->[1] } 
  map { [$_, -s] } 
  @files;
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So in principle you would do ST in the following step:

1. Map the initial list into a list of ref to lists with the original 
+and modified values 
2. Sort the list of references 
3. Map the list of ref back into a plain list with the initial values
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Check this out by the very creator himself - Randal Schwartz (merlyn).

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