{"id":83055,"date":"2020-05-28T01:42:15","date_gmt":"2020-05-27T23:42:15","guid":{"rendered":"https:\/\/prohoster.info\/blog\/administrirovanie\/kak-linuxovskij-sort-sortiruet-stroki"},"modified":"2020-05-28T01:42:15","modified_gmt":"2020-05-27T23:42:15","slug":"kak-linuxovskij-sort-sortiruet-stroki","status":"publish","type":"post","link":"https:\/\/prohoster.info\/ro\/blog\/administrirovanie\/kak-linuxovskij-sort-sortiruet-stroki","title":{"rendered":"Cum sorteaz\u0103 Linux sort liniile","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Introducere<\/h1>\n

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Totul a \u00eenceput cu un script scurt care ar fi trebuit s\u0103 uneasc\u0103 informa\u021biile despre adrese e-mail<\/em> angaja\u021bilor, ob\u021binute din lista de utilizatori ai buletinului informativ, cu func\u021biile angaja\u021bilor, ob\u021binute din baza de date a departamentului de resurse umane. Ambele liste au fost exportate \u00een fi\u0219iere text \u00een codificarea Unicode UTF-8<\/em> \u0219i salvate cu terminatori de linie Unix.<\/p>\n

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Con\u021binut mail.txt<\/em><\/p>\n

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Ivanov Andrei;ia@example.com<\/code><\/pre>\n
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Con\u021binut buhg.txt<\/em><\/p>\n
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Ivanova Alla;malear\nYelkina Ella;macara\u0219\nIvanov Andrei;instalator\nAbakanov Mihail;malear<\/code><\/pre>\n
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Pentru a le uni, fi\u0219ierele au fost sortate cu comanda Unix sort<\/em> \u0219i trimise ca intrare c\u0103tre programul Unix join<\/em>, care s-a \u00eencheiat brusc cu o eroare: <\/p>\n
<\/p>\n
$> sort buhg.txt > buhg.srt\n$> sort mail.txt > mail.srt\n$> join buhg.srt mail.srt > result\njoin: buhg.srt:4: nu este sortat: Ivanov Andrei;instalator<\/code><\/pre>\n
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Vizionarea rezultatului sort\u0103rii a ar\u0103tat c\u0103, \u00een general, sortarea este corect\u0103, dar \u00een cazul \u00een care exist\u0103 corespondente \u00eentre numele masculine \u0219i feminine, numele feminine apar \u00eenaintea celor masculine:<\/p>\n
<\/p>\n
$> sort buhg.txt\nAbakanov Mihail;malear\nYelkina Ella;macara\u0219\nIvanova Alla;malear\nIvanov Andrei;instalator<\/code><\/pre>\n
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Pare a fi un bug \u00een sortarea Unicode sau o manifestare a feminismului \u00een algoritmul de sortare. Prima variant\u0103 este, desigur, mai plauzibil\u0103.<\/p>\n
<\/a><\/noindex><\/p>\n
S\u0103 l\u0103s\u0103m deoparte join<\/em> \u0219i s\u0103 ne concentr\u0103m pe sort<\/em>. S\u0103 \u00eencerc\u0103m s\u0103 rezolv\u0103m problema prin \u00eencerc\u0103ri \u0219i erori. Pentru \u00eenceput, s\u0103 schimb\u0103m localitatea de la en_US<\/em> pe ru_RU<\/em>. Pentru sortare ar fi fost suficient s\u0103 set\u0103m variabila de mediu LC_COLLATE<\/em>, dar nu ne vom mul\u021bumi cu pu\u021bin:<\/p>\n
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$> LANG=ru_RU.UTF-8 sort buhg.txt\nAbakanov Mihail;malear\nYelkina Ella;macara\u0219\nIvanova Alla;malear\nIvanov Andrei;instalator<\/code><\/pre>\n
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Nimic nu s-a schimbat.<\/p>\n
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S\u0103 \u00eencerc\u0103m s\u0103 recodific\u0103m fi\u0219ierele \u00een codificarea pe un singur byte: <\/p>\n
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$> iconv -f UTF-8 -t KOI8-R buhg.txt \n | LANG=ru_RU.KOI8-R sort \n | iconv -f KOI8-R -t UTF8<\/code><\/pre>\n
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Din nou, nimic nu s-a schimbat.<\/p>\n
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Nu avem \u00eencotro, va trebui s\u0103 c\u0103ut\u0103m o solu\u021bie pe internet. Nu exist\u0103 informa\u021bii exact despre numele ruse\u0219ti, dar exist\u0103 \u00eentreb\u0103ri despre alte ciud\u0103\u021benii ale sort\u0103rii. Iat\u0103, de exemplu, o problem\u0103: unix sort trateaz\u0103 caracterele ‘-‘ (cratim\u0103) ca fiind invizibile<\/a><\/noindex>. \u00cen rezumat, \u0219irurile "a-b", "aa", "ac" sunt sortate ca "aa", "a-b", "ac".<\/p>\n
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R\u0103spunsul este standard peste tot: folose\u0219te localitatea de programare "C"<\/em> \u0219i va fi bine. S\u0103 \u00eencerc\u0103m:<\/p>\n
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$> LANG=C sort buhg.txt\nYelkina Ella;macara\u0219\nAbakanov Mihail;malear\nIvanov Andrei;instalator\nIvanova Alla;avocat<\/code><\/pre>\n
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S-a schimbat ceva. Ivanovii s-au aranjat \u00een ordinea corect\u0103, dar Iolkina a disp\u0103rut undeva. Revenim la sarcina ini\u021bial\u0103:<\/p>\n
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$> LANG=C sort buhg.txt > buhg.srt\n$> LANG=C sort mail.txt > mail.srt\n$> LANG=C join buhg.srt mail.srt > result<\/code><\/pre>\n
<\/p>\n
A func\u021bionat f\u0103r\u0103 erori, a\u0219a cum a promis internetul. \u0218i asta \u00een ciuda lui Iolkina \u00een prima linie.<\/p>\n
<\/p>\n
Problema pare s\u0103 fie rezolvat\u0103, dar pentru orice eventualitate vom \u00eencerca \u00eenc\u0103 o codare rus\u0103 - cea de Windows CP1251<\/em>:<\/p>\n
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$> iconv -f UTF-8 -t CP1251 buhg.txt \n | LANG=ro_RO.CP1251 sort \n | iconv -f CP1251 -t UTF8 <\/code><\/pre>\n
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Rezultatul sort\u0103rii, ciudat, va coincide cu localele "C"<\/em>, \u0219i \u00eentreaga demonstra\u021bie, \u00een consecin\u021b\u0103, trece f\u0103r\u0103 erori. E o adev\u0103rat\u0103 minune.<\/p>\n
<\/p>\n
Nu-mi place minunile \u00een programare, deoarece, de obicei, ele mascheaz\u0103 erorile. Va trebui s\u0103 m\u0103 ocup serios de \u00eentrebarea cum func\u021bioneaz\u0103 sort<\/em> \u0219i la ce influen\u021beaz\u0103 LC_COLLATE<\/em> .<\/p>\n
<\/p>\n
\u00cen final, voi \u00eencerca s\u0103 r\u0103spund la \u00eentreb\u0103rile:<\/p>\n
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