# Sort roman numerals **URL:** \ **Category:** Shell Programming and Scripting\ **Created:** [March 25, 2011, 7:45pm UTC](https://community.unix.com/t/sort-roman-numerals/285267 "2011-03-25T19:45:47Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![locoroco](https://community.unix.com/letter_avatar/locoroco/32/6_22734026db12803ebb3e059622ac3534.png) [@locoroco](https://community.unix.com/u/locoroco)\ **Post date:** [March 25, 2011, 7:45pm UTC](https://community.unix.com/t/sort-roman-numerals/285267/1 "2011-03-25T19:45:47Z")
If I use ls to print all the files of a folder, is there a way to sort using roman numerals? I am thinking about a result like: benjamin\_I.wmv benjamin\_II.wmv benjamin\_II.wmv benjamin\_III.wmv benjamin\_IV.wmv benjamin\_V.wmv benjamin\_VI.wmv benjamin\_VII.wmv benjamin\_VIII.wmv benjamin\_IX.wmv The roman numerals are always preceded by an underscore. ---
**Author:** ![mirni](https://community.unix.com/letter_avatar/mirni/32/6_22734026db12803ebb3e059622ac3534.png) [@mirni](https://community.unix.com/u/mirni)\ **Post date:** [March 25, 2011, 9:46pm UTC](https://community.unix.com/t/sort-roman-numerals/285267/2 "2011-03-25T21:46:25Z")
Your best bet is probably perl's 'Roman' module. Download Roman.pm from CPAN here: [http://search.cpan.org/~chorny/Roman-1.23/lib/Roman.pm](http://search.cpan.org/%7Echorny/Roman-1.23/lib/Roman.pm) copy it into /usr/lib/perl5/site\_perl/5.8.8/ (adjust to your perl version). Create a perl script sortRoman.pl: ```plaintext #!/usr/bin/perl -w use Roman; sub romanSort { #custom sorting definition $a =~ /^.*_([MDCLXVI]+)\..*/; #capture all roman numerals after underscore $aRom = arabic($1); #convert captured roman number to arabic (e.g. XIV --> 14 ) $b =~ /^.*_([MDCLXVI]+)\..*/; #repeat with second input $aRom <=> arabic($1); #numeric comparison between the converted numbers } @data = (<>); #slurp the whole input into one array print sort romanSort @data; #print sorted array using custom routine romanSort ``` make it executable ```plaintext chmod 754 sortRoman.pl ``` and try it out: ```plaintext $ cat testdata b_II.wmv b_III.wmv b_IX.wmv b_IV.wmv b_VI.wmv b_V.wmv b_VII.wmv b_CXLIV.wmv b_CXIV.wmv b_CXII.wmv A_B_XIV.wmv $ ./sortRoman.pl testdata b_II.wmv b_III.wmv b_IV.wmv b_V.wmv b_VI.wmv b_VII.wmv b_IX.wmv A_B_XIV.wmv b_CXII.wmv b_CXIV.wmv b_CXLIV.wmv ``` ---
**Author:** ![Corona688](https://community.unix.com/letter_avatar/corona688/32/6_22734026db12803ebb3e059622ac3534.png) [@Corona688](https://community.unix.com/u/Corona688)\ **Post date:** [March 25, 2011, 10:33pm UTC](https://community.unix.com/t/sort-roman-numerals/285267/3 "2011-03-25T22:33:49Z")
Egads... I'd translate the numbers from roman numerals into normal numbers, sort, then change them back. ```nohighlight # roman.awk # Adapted from a clever converter found here # http://scripts.mit.edu/~yfarjoun/homepage/index.php?title=Code_Snippets BEGIN { R["I"]=1; R["V"]=5; R["X"]=10; R["L"]=50; R["C"]=100; R["D"]=500; R["M"]=1000; E["iv"]="IIII"; E["ix"]="VIIII"; E["xl"]="XXXX"; E["xc"]="LXXXX"; E["cd"]="CCCC"; E["cm"]="DCCCC"; E["iix"]="VIII"; E["xxc"]="LXXX"; E["ccm"]="DCCC"; E["vl"]="XXXXV"; E["ld"]="CCCCL"; } function roman_arabic(RN) { SUM=0; RN=tolower(RN); # Substitute roman numeral forms into things we can count. # Substitue lower case for upper case so substitutions # don't happen twice by accident. for(K in E) while(sub(K, E[K], RN)); # Convert anything that didn't get substituted to uppercase. RN=toupper(RN); for(K in R) while(sub(K, "", RN)) SUM+=R[K]; return(SUM); } { split($0, ARR, /[_.]/); if($0 ~ /_[iIvVlLxXcCdDmM]+/) { # print ARR[1], ARR[2], ARR[3]; printf("%s_%s.%s\n", ARR[1], roman_arabic(ARR[2]), ARR[2], ARR[3]); } } ``` ```nohighlight $ awk -f roman.awk < list benjamin_I.wmv benjamin_VIII.wmv benjamin_IV.wmv benjamin_V.wmv benjamin_II.wmv benjamin_II.wmv benjamin_IX.wmv benjamin_VII.wmv benjamin_III.wmv benjamin_VI.wmv $ awk -f roman.awk < list | sort benjamin_I.wmv benjamin_II.wmv benjamin_II.wmv benjamin_III.wmv benjamin_IV.wmv benjamin_V.wmv benjamin_VI.wmv benjamin_VII.wmv benjamin_VIII.wmv benjamin_IX.wmv $ awk -f roman.awk < list2 | sort | sed -r 's###g' benjamin_I.wmv benjamin_II.wmv benjamin_II.wmv benjamin_III.wmv benjamin_IV.wmv benjamin_V.wmv benjamin_VI.wmv benjamin_VII.wmv benjamin_VIII.wmv benjamin_IX.wmv $ ``` ...but beware of all the valid words that can be made from roman numerals: ```nohighlight $ egrep -i "^[IVXLCRDM]{3}[IVXLCRDM]*$" /usr/share/dict/cracklib-small cdc cdr civic civil did dill dim drill icc iii ill lid lim livid mid mild mill mimi mimic mix rid rill rim vii viii vivid $ ``` ---
**Author:** ![centurion\_13](https://community.unix.com/letter_avatar/centurion_13/32/6_22734026db12803ebb3e059622ac3534.png) [@centurion\_13](https://community.unix.com/u/centurion_13)\ **Post date:** [March 28, 2011, 5:15am UTC](https://community.unix.com/t/sort-roman-numerals/285267/4 "2011-03-28T05:15:12Z")
> [@mirni](#): > > Your best bet is probably perl's 'Roman' module. > Download Roman.pm from CPAN here: [http://search.cpan.org/~chorny/Roman-1.23/lib/Roman.pm](http://search.cpan.org/%7Echorny/Roman-1.23/lib/Roman.pm) > copy it into /usr/lib/perl5/site\_perl/5.8.8/ (adjust to your perl version). > > Create a perl script sortRoman.pl: > > ```plaintext > #!/usr/bin/perl -w > > use Roman; > > sub romanSort { > $a =~ /^.*_([MDCLXVI]+)\..*/; > $aRom = arabic($1); > $b =~ /^.*_([MDCLXVI]+)\..*/; > > $aRom <=> arabic($1); > } > > @data = (<>); > > print sort romanSort @data; > > ``` > > make it executable > > ```plaintext > chmod 754 sortRoman.pl > > ``` > > and try it out: > > ```plaintext > $ cat testdata > b_II.wmv > b_III.wmv > b_IX.wmv > b_IV.wmv > b_VI.wmv > b_V.wmv > b_VII.wmv > b_CXLIV.wmv > b_CXIV.wmv > b_CXII.wmv > A_B_XIV.wmv > > $ ./sortRoman.pl testdata > b_II.wmv > b_III.wmv > b_IV.wmv > b_V.wmv > b_VI.wmv > b_VII.wmv > b_IX.wmv > A_B_XIV.wmv > b_CXII.wmv > b_CXIV.wmv > b_CXLIV.wmv > > ``` What does this arabic($1) stand for ???? ---
**Author:** ![mirni](https://community.unix.com/letter_avatar/mirni/32/6_22734026db12803ebb3e059622ac3534.png) [@mirni](https://community.unix.com/u/mirni)\ **Post date:** [March 28, 2011, 7:10am UTC](https://community.unix.com/t/sort-roman-numerals/285267/5 "2011-03-28T07:10:45Z")
@centurion_13: arabic() is a function defined in Roman.pm module, to convert roman number to arabic (e.g. ```nohighlight $a = "XLVII"; $b = arabic($a); # b==47 ``` That's what that Roman.pm module is made for. $1 references what was captured in a most recent regex with parentheses. I added comments to my original reply. ---
**Author:** ![drl](https://community.unix.com/user_avatar/community.unix.com/drl/32/542_2.png) [@drl](https://community.unix.com/u/drl)\ **Post date:** [March 28, 2011, 10:27am UTC](https://community.unix.com/t/sort-roman-numerals/285267/6 "2011-03-28T10:27:40Z")
Hi. The utility msort is in the Debian GNU/Linux repositories. It often makes life easy for complex sorting situations: ```nohighlight #!/usr/bin/env bash # @(#) s2 Demonstrate sort of roman numerals, msort. # http://freshmeat.net/projects/msort # Utility functions: print-as-echo, print-line-with-visual-space, debug. pe() { for i;do printf "%s" "$i";done; printf "\n"; } pl() { pe;pe "-----" ;pe "$*"; } db() { ( printf " db, ";for i;do printf "%s" "$i";done; printf "\n" ) >&2 ; } db() { : ; } C=$HOME/bin/context && [-f $C] && . $C ;msort msort --version | head -1 FILE=${1-data3} pl " Data file $FILE:" cat $FILE pl " Results, msort on roman numerals, field 2:" msort --quiet --line --position 2 --comparison-type numeric --number-system roman $FILE exit 0 ``` producing: ```nohighlight % ./s2 Environment: LC_ALL = C, LANG = C (Versions displayed with local utility "version"ker|rel er|rel, machine: Linux, 2.6.32-5-686, i686 Distribution : Debian GNU/Linux 6.0 GNU bash 4.1.5 msort 8.53 ----- Data file data3: file ii suffix file i suffix file iv suffix file iii suffix file c suffix ----- Results, msort on roman numerals, field 2: file i suffix file ii suffix file iii suffix file iv suffix file c suffix ``` If you do not use Debian, see the msort home page as noted in the script. Best wishes ... cheers, drl PS. I had trouble with older versions of msort on 64-bit Debian (lenny), but the version of msort on the current stable edition (squeeze) seems to work correctly, as noted above. ---
**Author:** ![Corona688](https://community.unix.com/letter_avatar/corona688/32/6_22734026db12803ebb3e059622ac3534.png) [@Corona688](https://community.unix.com/u/Corona688)\ **Post date:** [March 28, 2011, 11:02am UTC](https://community.unix.com/t/sort-roman-numerals/285267/7 "2011-03-28T11:02:10Z")
> [@mirni](#): > > @centurion_13: arabic() is a function defined in Roman.pm module, to convert roman number to arabic ...and in case it's unclear, "arabic" numerals are normal numbers, digits 0 through 9 etc.