Ah yes, sorting with the good old Schwartzian Transform and GRT. Brings back some happy memories!

Some Schwartzian Transform references:

• Schwartzian transform (wikipedia) (no wikipedia page for GRT it seems)
• The History of the Schwartzian Transform by brian_d_foy (perl.com)

Wow, the Schwartzian Transform features in one of PM's earliest historic nodes on Christmas Day 1999 by chromatic, one of the pioneer developers of the Everything Engine! Posting on Christmas Day shows chromatic must have enjoyed tinkering with the Schwartzian Transform as much as I did in the early years. :)

• Schwartzian Transform by chromatic (Dec 25 1999!)
• Schwartzian Transform by merlyn (2000)
• Schwartzian transform JAPH by davido (2003)
• What is "Schwarzian Transform" (aka Schwartzian) by GrandFather (2005)
• Old sorting paper holds the key to unlocking the secrets of the Schwartzian Transform by aufflick (2005)

Nowhere near as many references for GRT:

• Advanced Sorting - GRT - Guttman Rosler Transform by demerphq (2002) - that GRT is tricky is shown by this 2003 necropost (by me!) pointing out a bug that lay undetected for 18 months in a node with 264 rep!
• Understanding transformation sorts (ST, GRT), the details by 5mi11er (2005)
• GRT sort with filetypes and GRT sort of files by time by blazar (2007) (Sadly, blazar is no longer with us, a real character, I still miss him)

Still fewer for the Orcish Manoeuvre:

• (Ovid) Re: Orcish Maneuver by Ovid (2001)
• Re: Challenge: sort weekdays in week-order (elegantly and efficiently) by kcott (2022) and replies

• Sort::Maker by Uri Guttman

Most of the eleven gold stars in Illuminations (category: sorting) were awarded to historical figures, including two gold stars to PM founder vroom himself:

• How do I do a complex sort on an array? by vroom (Jan 08, 2000) - answers from vroom, merlyn
• How do I sort a list of numbers? by vroom (Jan 21, 2000) - answered by vroom
• How do I sort a multidimensional arrays? by anonymonk (May 28, 2000) - answers from reptile, merlyn, chromatic
• How do I write my own sorting routine? by Russ (Jul 05, 2000) - answered by Russ
• How do I sort on more than one column? by Russ (Jul 23, 2000) - answered by Russ
• How do I sort a list chronologically from most recent to last? by anonymonk (Oct 28, 2000) - answer from chromatic

• How do I do a natural sort on an array? by anonymonk (Mar 30, 2001) - answers from indigo, tye, Dominus, salva
• How do I sort something by date? by damian1301 (May 31, 2001)
• How do I sort a Hash of Hashes? by greywolf (Jan 10, 2004)
• How do I use a sort routine from a different package/module? by bobf (Jun 09, 2005)
• How do I print the values of a hash, sorted by the hash keys? by kwaping (Jul 21, 2006)

See also:

• A brief tutorial on Perl's native sorting facilities. by BrowserUk (2007)
• fast, flexible, stable sort by tye (2003)
• Resorting to Sorting by japhy (2001)

External Sorting

On CPAN:

• Sort::External by Marvin Humphrey aka creamygoodness
• Sort::External::Cookbook by Marvin Humphrey aka creamygoodness
• File::Sort

By creamygoodness (author of Sort::External):

• Re: In-place sort with order assignment
• Re^3: Sorting a (very) large file
• Re^2: Problem with Sort::External 0.16
• Re^3: Sorting KinoSearch results
• Re: 'sort -u' in perl
• Re: RFC: yet another sorting technique (mentions Sort::External::Cookbook)

Super-fast sorting modules by salva:

• Sort::Packed
• Sort::Key
• Sort::Key::Radix
• Sort::Key::Multi
• Sort::Key::Natural

CPAN List::AllUtils sorting functions:

• sort_by
• nsort_by
• rev_sort_by
• rev_nsort_by

Other:

• external sort performance improved? by rkshyam (2012)
• Problem with Sort::External 0.16 by anonymonk (2008)
• Sorting (GRT) and locale issues

References Added Later

• Long list is long by Chuma (2022) - Hitting memory problems while sorting 2064 files (each one up to a couple hundred MB)
• Rosetta Code: Long List is Long by me (2022) - Sort performance was crucial in this long-running node

• Re: Long list is long by tybalt89 (2022) - examples using the sort command on various Unix flavours
• Re: Long list is long by marioroy (2023)* - Love letter to Chuma. :) parallel sorting with parsort/GNU Parallel, mcesort, parallel-hashmap, ... lots of extra references added later: g++, clang++, nvc++ using many different libraries
• Re: Rosetta Code: Long List is Long - GNU Parallel by marioroy (2023) - ditto
• Re^10: Rosetta Code: Long List is Long (faster - llil4vec - llil4judy - TBB code - llil5vec - boost) by me (2022) - where Boost's sort::block_indirect_sort parallel sort algorithm, running on 8 threads simultaneously, was massively faster than ANSI C++ std::sort

• Re: Rosetta Code: Long List is Long - JudySL code by marioroy (2023) - JudySL array implementation
• Solving the Long List is Long challenge, finally? by marioroy (2023) - Perl versions in replies use Sort::Packed, Tie::Hash::DBD, DB_File, IPC::MMA, Crypt::xxHash, Tokyo Cabinet, Kyoto Cabinet, Tkrzw sharding

• Re^6: Rosetta Code: Long List is Long (Updated Solutions - GRT) by me (2022) - GRT sort "out-marioroy-ed" marioroy :)
• Re^2: Rosetta Code: Long List is Long (Updated C++ Solutions) by me (2022) - issues around stable vs non-stable sorts, in Perl and C++
• Re: Rosetta Code: Long List is Long (Updated Solutions) by me (2022) - surprising Perl massive performance improvement by changing: sort { $href->{$b} <=> $href->{$a} || $a cmp $b } keys %{$href} to: sort { $href->{$b} <=> $href->{$a} } sort keys %{$href}

• sort of misunderstanding of sort by Discipulus (2023) - meditation on sorting
• Notation of sort function by Alphaphi (2023) - why we have to specify same operation for $a and $b? (redundancy?) - lots of useful replies (e.g. this one by hv :)
• Re^3: Notation of sort function (see replies by tybalt89 and ikegami using List::AllUtils and Sort::Key)
• Re: Are blessings a new thing? by me (2023) - early gold-star sorting nodes by significant PM historical figures, including vroom, merlyn, chromatic

• Sort array by IB2017 (2020)
• How do I sort an array by anything (perlfaq4)
• Sorting chapter in Mastering Algorithms with Perl O'Reilly book by Jon Orwant

• sorting very large text files by rnaeye (2009) - lots of responses from BrowserUk ... though it's hard to beat the system sort, some marioroy responses from Rosetta Code: Long List is Long might be worth a try in this old node (if rnaeye is still interested :-)

• A Fresh Look at Efficient Perl Sorting - paper by Uri Guttman (sysarch) and Larry Rossler
• YA Perl Advent Calendar by William 'N1VUX' Ricker of Boston.PM (2005)

Updated: Extra references added long after the original reply was made.