Hlela imisebenzi ku-Linux usebenzisa i-Crontab

Uma usebenzisa i-Linux nsuku zonke, uzodinga ukuthi isetshenziswe ngokushesha noma kamuva. Yenza imisebenzi ephindaphindwayo isebenze ngokuzenzakalelayo nge-Cron ne-CrontabUkusekela ngokulondoloza, izibuyekezo, ukwenziwa kwemibiko, ukuhlanzwa kwamafayela, ukuqapha… Ukwenza konke lokho ngesandla kudla isikhathi futhi kulula ukukukhohlwa. Yilapho i-Cron ingena khona, itshe eliyisisekelo lokuphathwa kohlelo lwe-Unix ne-GNU/Linux amashumi eminyaka.

Nakuba ekuqaleni i-syntax ye-Crontab ingase ibonakale iyesabisa kancane, uma usuyiqonda indlela enengqondo ngayo uzobona ukuthi Ukuhlela imisebenzi ku-Linux nge-Crontab kulula kakhulu kunalokho okubonakalaLesi sihloko sinikeza umhlahlandlela ophelele: ukuthi iyini i-Cron, iyini i-Crontab, indlela yokubhala imithetho, indlela yokulungisa amaphutha, umthelela wayo ongaba khona ekusebenzeni, amathuluzi angaphandle ongawasebenzisa, ezinye izindlela kwezinye izinhlelo, kanye namacala okusetshenziswa ekhaya nasebhizinisini.

Umehluko phakathi kwe-Cron ne-Crontab

UCron noCrontab bavame ukukhulunywa ngabo sengathi bayinto efanayo, kodwa empeleni Ziyizingxenye ezimbili ezahlukene ezisebenzisana.Ukuqonda lo mehluko kuzokusindisa enkingeni enkulu uma kufanele ulungise amaphutha emisebenzini engasebenzi.

• I-Cron Yi-daemon esebenza ngemuva kusukela ngesikhathi uhlelo luqala. Umsebenzi wayo ulula kakhulu: buyekeza uchungechunge lwamafayela okucushwa njalo ngeminithi futhi uhlole ukuthi kukhona yini imisebenzi ehleliwe okudingeka yenziwe ngokuvumelana nosuku nesikhathi sesistimu.
• QondisaNgakolunye uhlangothi, yi- ifayela lombhalo lapho leyo misebenzi ichazwa khonaUmsebenzisi ngamunye angaba nefayela lakhe le-crontab, elinemithetho nezikripthi zakhe, ezisetshenziswa ngemvume yakhe. I-Cron daemon ifunda lawa mafayela futhi isebenzisa imiyalo uma kufanele.

Kunoma yikuphi ukusatshalaliswa kwe-Linux yesimanje uzothola zombili izingxenye ezitholakala ngokuzenzakalelayo, ngakho-ke Ungahlela imisebenzi ephindaphindwayo cishe kunoma iyiphi i-distro, kungaba yi-Debian, Ubuntu, Oracle Linux, CentOS, Rocky, Fedora, njll.

Kuyini i-Cron futhi kungani isikhathi sesistimu sibalulekile?

UCron ungumuntu i-daemon yesistimu eqala lapho i-Linux iqalaNgokuvamile iqaliswa ngezikripthi ze-boot zakudala ku /etc/init.d noma emizileni efanayo efana /etc/rc.dnoma ukusebenzisa amayunithi e-systemd (i-service crond noma i-cron, kuye ngokuthi i-distro iyatholakala kanjani). Ihlola njalo ngemizuzu:

/etc/crontab, /etc/cron.d, /var/spool/cron kanye /var/spool/cron/crontabs (Indlela eqondile iyahlukahluka kuye ngokusatshalaliswa), ifuna okufakiwe okufana nomzuzu wamanje. Uma ithola noma yikuphi, isebenzisa umyalo obonisiwe.

Into abantu abaningi abayinaki ukuthi I-Cron ithembele ngokuphelele esikhathini sesistimuUma iwashi noma indawo yesikhathi ingasethiwe kahle, imisebenzi yakho izosebenza ngezikhathi ezingafanele. Ukuze uhlole isikhathi ezinhlelweni zesimanje, ungasebenzisa:

timedatectl

Lo myalo ubonisa isikhathi sendawo, i-UTC, indawo yesikhathi, nokuthi uhlelo luyavumelanisa yini namaseva e-NTP (Network Time Protocol). Okungcono kakhulu, Ukuvumelanisa kwe-NTP kuyasebenzangoba ngaleyo ndlela iwashi lizilungisa ngokuzenzakalelayo.

Uma ubona ukuthi indawo yesikhathi ayilungile, ungayishintsha ngento efana nale isikhathi setha-isikhathi sendawo iYurophu/iMadrid noma enye indawo efana nezwe lakini. Futhi, ekufakweni okuningi kwe-Linux, i-NTP ihlelwa ngokuzenzakalelayo, kodwa uma ufuna ukuyenza ngokwezifiso, unga... /etc/ntp.conf noma sebenzisa izinsizakalo ezihlukile njenge-chrony.

Iyini i-Crontab futhi yakhiwe kanjani?

I-Crontab yi- ifayela lapho ubhala khona imithetho yokusebenza yemisebenzi yakho ehleliweUmugqa ngamunye (ukunganaki amazwana) umele "umsebenzi": ukuthi usebenza nini nokuthi umyalo usetshenziswa muphi. Ngokuvamile, umsebenzisi ngamunye une-crontab yakhe kufolda ye-spool. / var / spool / cron o /var/spool/cron/crontabs, ngokusho kwe-distro.

Ukuze uphathe i-crontab yakho yomuntu siqu, sebenzisa umyalo i-crontab ngezinketho eziningana eziyisisekelo kodwa ezinamandla. Amafayela awahlelwa ngesandla ngomhleli ongahluziwe, kodwa ahlelwa ngalo myalo ukuze kugwenywe imvume noma amaphutha okufometha.

I-syntax eyisisekelo yomugqa owodwa ku-Crontab isekelwe ku- amasimu ezikhathi ezinhlanu kanye nomyalo:

m h dom mon dow comando

• Iminithi (m): amanani asukela ku-0 kuya ku-59.
• Ihora (h): amanani kusukela ku-0 kuya ku-23.
• Usuku lwenyanga (Ilanga): kusukela ku-1 kuya ku-31.
• mes (mon): kusukela ku-1 kuya ku-12 noma igama elifingqiwe (Jan, Feb, njll., ngokusho kohlelo).
• Usuku lweviki (phansi): kusukela ku-0 kuya ku-6 noma ku-0 kuya ku-7, kanti iSonto lingu-0 (futhi ngezinye izikhathi no-7).
• Umyalo: noma yimuphi umyalo ongawusebenzisa ku-terminal, kufaka phakathi izikripthi kanye nokuqondisa kabusha.

Isibonelo esijwayelekile singaba:

00 19 * * * /home/usuario/scripts/backup.sh

Lo mugqa ubonisa ukuthi iskripthi sizokwenziwa nsuku zonke ngo-19:00 ntambama (7 ntambama), kungakhathaliseki ukuthi usuku lwenyanga, inyanga, noma usuku lwesonto.

Indlela yokudala, ukuhlela, nokufaka ohlwini i-Crontab yakho

Ukuze usebenze ngefayela lakho lemisebenzi yomuntu siqu, cishe njalo usebenzisa umyalo ngokwawo. i-crontab. Umqondo wukuthi Ungawahleli ngesandla amafayela ku-/var/spool/cron/crontabs, njengoba zenzelwe ukuphathwa ngokuzenzakalelayo uhlelo.

Ama-oda avame kakhulu yilawa:

• i-crontab-eVula i-crontab yakho kusihleli sakho sombhalo esizenzakalelayo (ezindaweni eziningi zokusabalalisa) vim o umfowethu omdala) ukudala noma ukuguqula okufakiwe.
• i-crontab -l: ibonisa esikrinini yonke imisebenzi ehlelelwe umsebenzisi wakho.
• i-crontab -rSusa yonke i-crontab yakho; lesi yisenzo esingenakuguqulwa. Akuceli ukuqinisekiswa uma ungangezi i--i.
• i-crontab -i -r: icela isiqinisekiso ngaphambi kokususa i-crontab.
• ifayela le-crontab: shintsha i-crontab yakho yamanje ngokuqukethwe kwefayela elichaziwe.
• crontab -u umsebenzisi: phatha i-crontab yomunye umsebenzisi (impande kuphela noma leyo enezimvume).
• crontab -c dir: Kumasistimu ayisekelayo, kuchaza uhlu lwemibhalo lapho i-crontab izogcinwa khona.

Uma ufuna ukwenza isipele sezilungiselelo zakho, ungenza into elula njengokuthi:

crontab -l > ~/crontab_backup.txt

Futhi uma udinga ukuyibuyisela kamuva, mane nje:

crontab ~/crontab_backup.txt

I-syntax ethuthukisiwe: izinhlamvu ezikhethekile ku-Crontab

Ngaphezu kwezinombolo, i-Crontab ikuvumela ukuthi usebenzise Izinhlamvu ezikhethekile ezenza i-syntax iguquguquke kakhuluNgenxa yabo ungaveza amabanga, uhlu noma izikhawu ngendlela ehlangene.

• * (inkanyezi): ikhombisa "wonke amanani angenzeka" kuleyo nsimu. Isibonelo, * ensimini yamahora Kusho wonke amahora.
• , (ukhefana): eyodwa ehlukile uhlu lwamanani athile. Isibonelo: 0 6,18 * * * Isebenza ngo-6:00 nango-18:00.
• - (iskripthi): ichaza a ububanzi obuqhubekayo. Isibonelo: 0 8-17 * * 1-5 Isebenza njalo ngehora kusukela ngo-8 ekuseni kuya ku-17 ntambama, ngoMsombuluko kuya kuLwesihlanu.
• / (ukusikwa): maka eyodwa isinyathelo noma isikhawu. Isibonelo */10 * * * * kusho ukuthi "njalo ngemizuzu eyi-10."
• ububanzi/ngaphandle (kuye ngokuthi kusetshenziswe kanjani): ezinye izinhlobo zivumela ukuchaza amanani angafakiwe, yize lokhu kungeyona ejwayelekile kuyo yonke imisebenzi ye-cron.

Isibonelo esijwayelekile sokusetshenziswa okuhlangene singaba:

*/5 2 * * 1-5 /bin/ejecutar/script.sh

Lo mugqa uqala umyalo njalo ngemizuzu emi-5 phakathi nehora lesi-2 (2:00) kusukela ngoMsombuluko kuya kuLwesihlanuKuyindlela encane yokushintsha uhlu olude lwemizuzu.

Umlingiswa # (hashi) ekuqaleni komugqa kusebenza engeza imibonoKonke okulandelayo ngemva kwalolo phawu emgqeni ofanayo akunakwa, okuyinto efanele kakhulu ekubhaleni ukuthi kungani umsebenzi ukhona noma ukuwukhubaza okwesikhashana ngaphandle kokuwususa.

Amagama angukhiye nezinqamuleli zesikhathi ku-Crontab

Ezimweni ezivame kakhulu, i-Crontab inikeza izinqamuleli ngendlela "yamagama agciniwe" Lezi zithatha indawo yezinkambu zesikhathi zonke. Ziwusizo kakhulu uma ufuna into efana nokuthi "nsuku zonke" noma "njalo ngehora" ngaphandle kokucabanga ngezinombolo.

• @qalisa kabusha: ukhipha umyalo uma uhlelo seluqalile.
• @ngonyaka o @ngonyaka: kanye ngonyaka, okulingana 0 0 1 1 *.
• @ngenyanga: kanye ngenyanga, ngosuku lokuqala phakathi kwamabili, okulingana 0 0 1 * *.
• @ngeviki: kanye ngesonto, phakathi kwamabili ngosuku 0 (ngokuvamile ngeSonto), okulingana no I-0 0 * * 0.
• @nsuku zonke o @midnight: kanye ngosuku, ngo-00:00, okulingana no I-0 0 * * *.
• @ngehora: kanye njalo ngehora, ngomzuzu ongu-0, okulingana no 0 * * * *.

Isibonelo, uma ufuna iskripthi sisebenze njalo ngehora, kwanele nge:

@hourly /bin/ejecutar/script.sh

Futhi uma ufuna ukuthi iskripthi sokulungisa siqale ngemva kokuqala kabusha ngakunyeUzosebenzisa:

@reboot /ruta/a/mi_script.sh

Izinguquko zemvelo kanye ne-syntax yomyalo

Umthombo ojwayelekile wamaphutha ukuthi I-Cron isebenza endaweni encane kakhuluAkukukhokhisi .bashrc noma yonke indawo yakho yomsebenzisi, ngakho-ke I-PATH incane kakhulu (ngokuvamile kuyinto efana /usr/bin:/binLokhu kwenza imiyalo ifane I-Python, i-Git, i-PHP, noma i-Pip Azikwazi ukutholakala uma ungasebenzisi indlela ephelele.

Ukuze ugweme lokhu, unezinketho ezimbili: Sebenzisa imizila ephelele njalo ezikriphthini zakho (isibonelo, /usr/bin/python3 esikhundleni se python) noma Chaza iziguquguquko zemvelo ekuqaleni kwe-crontab yakhoIsibonelo kungaba:

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
SHELL=/bin/bash
HOME=/home/usuario

Le migqa ibekwe ekuqaleni kwefayela le-crontab, ngaphandle kwezinkambu zesikhathifuthi kuthinte eminye imisebenzi oyimemezelayo ngezansi. Ungachaza futhi I-MAILTO ukukhombisa ukuthi umkhiqizo ojwayelekile kanye nephutha lemisebenzi uthunyelwa kuliphi ikheli le-imeyili.

Khumbula lokho Imiyalo ku-Crontab yamukela yonke i-syntax yegobolondoUngaqondisa kabusha okukhiphayo kufayela, imiyalo yochungechunge ngamapayipi, njll. Isibonelo, ku londoloza konke okukhipha iskripthi ku-log:

* * * * * /home/usuario/helloworld.sh >> /var/log/logs.log 2>&1

Futhi uma ufuna thulisa imiyalezo ngokuphelele futhi ungatholi i-imeyili Kulowo msebenzi, ungaqondisa kabusha ku- / dev / null:

* * * * * /home/usuario/helloworld.sh >/dev/null 2>&1

Ukuphathwa kokukhipha: izingodo kanye ne-imeyili

Kuye ngokusatshalaliswa kanye nokucushwa, okukhiphayo kwe-Cron kungaphathwa ngezindlela eziningana. Kuzinhlelo ezifana ne-Oracle Linux noma i-Debian encane, uma kungekho i-ejenti yeposi efakiwe, I-cron daemon ithumela umphumela ngqo ohlelweni lokungena ngemvume..

Ezimweni eziningi ungabuka umsebenzi we-cron kumafayela afana nalawa:

• /var/log/cron (okuvamile ku-Oracle Linux, CentOS, RHEL).
• / var / log / syslog (okuvamile ku-Debian kanye nama-derivatives).

Isibonelo, ngoba hlunga imiyalezo ehlobene ne-cron kuphela Kuhlelo olusebenzisa i-syslog, ungenza into efana nalokhu:

grep CRON /var/log/syslog

Ulwazi luvame ukuba lufushane (isikhathi, umsebenzisi, umyalo), kodwa lukusiza ukuthi ubone ukuthi kukhona yini okusebenzayo noma ukuthi kuyahluleka.

Uma ufaka i-Mail Transport Agent (MTA) njenge Ukulungiswa kweposi noma i-Sendmail, bese kuthunyelwa umphumela wemisebenzi emgqeni weposi wendawo womsebenzisiNgokuvamile igcinwa ku- /var/spool/mail/$USER noma imizila efanayo, futhi ungayifunda ngamathuluzi afana nalawa i-mailx (umyalo mail).

Ngaphezu kwalokho, ungalawula umamukeli wama-imeyili e-cron usebenzisa i-variable I-MAILTO ekuqaleni kwe-crontab:

MAILTO="[email protected]"

Uma ushiya i-MAILTO ingenalutho esikhundleni salokho, kanje:

MAILTO=""

Khona-ke Akukho imeyili ezothunyelwa nganoma yimiphi imisebenzi echazwe kuleyo crontabLokhu kuyasiza uma unemisebenzi eminingi ekhiqiza umphumela oqhubekayo.

Amathuluzi nezinsiza zokusebenza neCron

Uma ungakhululekile ukubhala izinkulumo ze-cron ngesandla, kunezindlela eziningana Amathuluzi akusiza ukuthi udale imithetho ngaphandle kokwenza amaphuthaEzinye ziyizinsizakalo zewebhu, ezinye ziyizinhlelo zokusebenza zezithombe.

• I-Crontab Guru: Ikhasi eliwusizo kakhulu lapho ubhala khona inkulumo ye-cron bese... Chaza ngombhalo ofundeka kalula ukuthi wenzaniIkwazisa ngamaphutha futhi inikeza izibonelo namathiphu avamile.
• Ijeneretha Yomsebenzi we-CronUmsizi we-inthanethi wokukhiqiza izinkulumo ze-cron kusuka kuzinketho ezifana nesikhathi, usuku, isikhawu, njll. Ikuvumela ukuthi udale imisebenzi ephindaphindayo nge izilungiselelo ezichazwe ngaphambilini futhi uzenze zibe ngezifiso.
• I-EasyCron: isevisi yamafu ye hlela izicelo ze-HTTP kuma-URL ngezikhathi ezithile ezibekiwe. Isetshenziswa kabanzi ukuqalisa izikripthi zewebhu, imisebenzi ye-API, njll., ngephaneli yokulawula, amalogi, kanye nezaziso ze-imeyili.
• I-KDE Cron (KCron): ithuluzi lesithombe elihlanganiswe endaweni ye-KDE ye Dala, shintsha, futhi ususe imisebenzi ye-cron ngaphandle kokuthinta umugqa womyaloIkuvumela ukuthi ukhethe izikhathi nezinsuku kusuka ku-interface ebonakalayo.
• Umenzi we-Cron: ijeneretha yokuveza i-cron eku-inthanethi eyenzelwe hlanganisa nomtapo wezincwadi we-Quartz (isetshenziswa kabanzi ezindaweni zeJava), kodwa futhi iwusizo ekuqondeni inhlanganisela eyinkimbinkimbi.

Lezi zinsiza azithathi indawo ye-Cron ohlelweni lwakho, kodwa Zenza kube lula ukwakheka kwengxenye yenkulumoukunciphisa amaphutha e-syntax.

Izinhlobo ze-Crontab: uhlelo kanye nomsebenzisi

Ku-Linux kunezinhlobo ezimbili eziyinhloko zamafayela okucushwa kwemisebenzi ehleliwe: i- i-crontab yesistimu futhi i i-crontab yomsebenzisiZombili zisebenzisa isichazamazwi esifanayo kakhulu, kodwa aziphathwa ngendlela efanayo.

El I-Cronab yesistimu, ngokuvamile ku / njll / crontab kanye nakumafayela e- /etc/cron.d, ngokuvamile kudinga izimvume zezimpandeIsetshenziselwa imisebenzi ebalulekile yesistimu (ukujikeleza kwamalogi, ukulungiswa kwedatha, imisebenzi yokusekelayo yezinga eliphezulu, njll.) futhi, ngokungafani ne-crontab yomsebenzisi, ifaka ngokusobala insimu yomsebenzisi emgqeni ngamunye ukuze ibonise Lo myalo uqhutshwa ngobuni?.

I-Los I-crontab yomsebenzisi ziphathwa nge i-crontab-e futhi zigcinwa ku- /var/spool/cron/crontabs noma indawo efanayo. Umsebenzisi kuphela ongathumela imisebenzi yakhe. (noma impande, ongakwazi ukuphatha imisebenzi ye-cron yabanye), futhi akufanele ihlelwe ngqo. Ukuze ukhawulele ukuthi obani abangasebenzisa i-cron, ungashintsha amafayela /etc/cron.allow y /etc/cron.deny.

Umthelela we-Cron ne-Crontab ekusebenzeni

Nakuba iCron ngokwayo isebenzisa izinsiza ezimbalwa kakhulu, ukuhlela imisebenzi okungekuhle kungenza kuthinta kabi ukusebenza kohleloInkinga ngokuvamile akuyona i-cron daemon, kodwa yilokho esikuyala ukuba kusebenze.

Uma uhlela imisebenzi eminingi ukuthi iqale ngesikhathi esisodwa, ungabangela Izinga lokusetshenziswa kwe-CPU ne-RAMIsibonelo, ukusebenzisa ama-backups amathathu amakhulu, i-reindexing yedathabheyisi, kanye neskripthi sokuhlaziya amalogi ngesikhathi esifanayo cishe kuyisiqinisekiso sokuthi iseva izoncipha.

Uma imisebenzi ihilela ukuxhumana (amakhophi akude, ukuvumelanisa nge-rclone(ukudluliselwa kwedatha ngobuningi), ungakha ukugcwala kwe-bandwidth, ukubambezeleka okwandisiwe, kanye ne-pingokuthinta ezinye izinsizakalo ezincike ekuxhumekeni.

Kukhona futhi ingozi izingxabano zomsebenziIzikripthi ezimbili ezisebenza ngesikhathi esisodwa kufayela elifanayo noma kusizindalwazi esinemisebenzi ehlukene zingabangela ukonakala kwedatha noma ukwehluleka okungajwayelekile okunzima ukukuthola.

Ukuze unciphise umthelela, ungasebenzisa amathuluzi anjenge nice ukunciphisa ukubaluleka kwe-CPU yomsebenzi, noma i-cpulimit ukukhawulela iphesenti eliphezulu le-CPU elingadliwa yinqubo:

• Ukubaluleka kwe-CPU okuphansi:
  0 19 * * * usuario nice -n 19 /ruta/script.sh
• Nciphisa i-CPU ibe ngu-50%:
  0 19 * * * usuario cpulimit -l 50 /ruta/script.sh

Ukusebenzisa i-Crontab emisebenzini evamile: ukwenza amakhophi agciniwe, ukuhlanza, kanye nokuqapha

Enye yezinzuzo ezinkulu zeCron ukuthi ikuvumela ukuthi yenza ngokuzenzakalelayo "ukulungiswa" komshini wakho cishe kalula, kuthuthukisa ukusebenza kwesikhathi esimaphakathi futhi konga isikhathi.

Ukusetshenziswa okujwayelekile kakhulu hlanza amafayela esikhashana, ama-cache, kanye nezinhlu zemibhalo ezingenalutho ngezikhathi ezithileNgeskripthi esisusa amafayela amadala noma angenalutho ezindleleni ezithile, ungakhulula isikhala futhi unciphise ukuqhekeka kwesistimu yamafayela.

Enye iphethini ewusizo yile uhlelo lwesimiso kanye nezibuyekezo zohlelo lokusebenza ngesikhathi esingekho emsebenzini omkhulu. Isibonelo, umsebenzi wasebusuku oqalayo i-apt update && ukuthuthukiswa okufanelekile (noma okulinganayo ku-distro yakho) kuvumela uhlelo ukuthi lubuyekezwe ngaphandle kokuphazamisa umsebenzi wansuku zonke.

Ungakwazi futhi ukwenza ngokuzenzakalelayo ukuvala izinhlelo zokusebenza ebezingasebenzi isikhathi eside kakhuluukukhulula inkumbulo yezinye izinqubo. Ezindaweni zedeskithophu noma zeseva yohlelo lokusebenza, lokhu kungenza umehluko omkhulu.

Futhi, vele, i-Cron ilungele kahle izikripthi zokuqapha nokurekhodaBamba njalo i-CPU, i-RAM, ukusetshenziswa kwediski, ukubambezeleka kwenethiwekhi, njll., kugcine kumafayela elogi, bese uhlaziya izitayela ukuze uthole izithiyo ngaphambi kokuba zibe yizigameko ezinkulu.

Okubi kanye nokulinganiselwa kwe-Cron kanye ne-Crontab

Nakuba i-Cron iyithuluzi elinamandla kakhulu, akuyona ikhambi eliphelele lakho konke. Imikhawulo okufanele ukwazi ukuze singayicindezeli ngaphezu kwalokho ekunikezayo.

Ngakolunye uhlangothi kukhona i- ijika lokufundaUma uvela ezindaweni noma izinhlelo ezinemifanekiso efana ne-Windows, kungaba yinto esabekayo ekuqaleni ukubhala ama-cron expression ngesandla bese usebenza ngaphandle kwesibonisi esibonakalayo.

Ngakolunye uhlangothi, i-Cron ixhumene kakhulu ne-Unix/Linux ecosystem. Lokho okufundayo kuzoba wusizo kumaseva amaningi nezinhlelo ezifanayo, kodwa Ngeke ukwazi ukuyisebenzisa njengoba injalo ku-Windows noma ku-macOS (enezindlela zayo).

Ngokuphathelene nokuphepha, uma Amafayela okucushwa kwe-cron awavikelwe kahleKungaba yindawo yokungena kokubulawa okunonya. Ukuvumela noma yimuphi umsebenzisi ukuthi ahlele izinto ngaphandle kokulawula kuvula ithuba lezinkinga.

Ngaphezu kwalokho, uCron Akufanelekile emisebenzini eyinkimbinkimbi kakhulu noma imisebenzi enokuncika okuningi.Ayiphathi ukugeleza kwamaphutha ngendlela ethuthukisiwe, ayikwazi ukuzama kabusha nge-conditional logic, futhi ayihlanganisi ngokwendabuko nezinhlelo ezisatshalaliswayo. Ngenxa yalokho, kunezihleli eziyinkimbinkimbi kakhulu noma izibali zesikhathi ze-systemd.

Futhi khumbula ukuthi i-crontab inikeza ukunemba komzuzu owodwa kuphelaUma udinga into egijima izikhathi eziningana ngomzuzwana noma ngezikhawu ezingaphansi komzuzu owodwa, kuzodingeka usebenzise amanye amathuluzi noma ama-loop ohlelo ngaphakathi kweskripthi ngokwaso.

Ezinye izindlela zokusebenzisa i-Cron ne-Crontab: i-Anacron, i-Fcron, i-hcron, i-Mcron nezinye

Kwezinye izimo, i-Cron ayifaneleki kahle. Isibonelo, uma une-laptop noma iseva engavulwanga njalo, Imisebenzi ehlelelwe isikhathi esithile ingalahleka uma imishini icishiwe ngaleso sikhathi.

Ukuze kuhlangatshezwane namacala anjalo, kunezinye izindlela ezifana nalezi: I-Anacron, eklanyelwe ukwenza imisebenzi yezikhathi ezithile ngaphandle kokufuna ukuthi umshini uhlale usebenzaUma ikhompyutha yayivaliwe ngesikhathi umsebenzi usuphelile, i-Anacron izoyiqalisa ngokushesha okukhulu ngemva kokuqalisa.

I-Fcron Kungenye inketho ethakazelisayo. Akudingi ukuthi uhlelo luhlale lusebenza; lungasebenza nalo izinsuku nezikhathi ezithile, futhi inikeza ukuguquguquka okwengeziwe ngezindleko zokudinga ukufakwa ngesandla kuma-distro amaningi.

i-hcron Kuhamba ibanga elide, okuvumela ukusetshenziswa kwe Amalebula okuhlela imisebenzi, ukuphatha amanethiwekhi emishini, kanye nokuthuthukisa ukuphephaAkuthandwa kangako, kodwa kungangena kahle ezindaweni lapho kudingeka khona ukuphathwa okuhlanganisiwe.

UMcCon (ngokusekelwe ku-Guile) ihlukile ngokuthi incike olimini oluphelele lokuhlela ukuze ichaze ukuhlela imisebenzi, okwenza kube amandla amakhulu uma kukhulunywa ngokuchaza kabusha imisebenzi, ukudala ukuncika, kanye nokusingatha ukucabanga okuyinkimbinkimbi.

Ku-Windows, kusetshenziswa izixazululo ezifana ne-Cron esikhundleni salokho. I-WinCron, i-VisualCron noma i-Advanced Task Schedulerezihlinzeka ngezixhumi ezibonakalayo zezithombe kanye nemisebenzi efanayo, yize zihlanganiswe ne-Microsoft ecosystem.

I-Cron ne-Crontab ezindaweni zebhizinisi

Ezinkampanini zabo bonke osayizi, i-Cron ne-Crontab ziyingxenye "yeglue" egcina izinhlelo zisebenza. Zivumela zenzeka ngokuzenzakalelayo izinqubo eziphindaphindwayo nezibucayi ngaphandle kokungenelela komuntu njalo, kunciphisa ingozi yokwehluleka nokukhulula isikhathi sabaphathi.

Phakathi kwezinto ezisetshenziswa kakhulu ebhizinisini kukhona Ama-backups ahleliwe, izibuyekezo zesofthiwe, ukukhiqizwa kwemibiko ngezikhathi ezithile, imisebenzi yokulungisa isizindalwazi, kanye nokuhlanzwa kwamalogiNgenxa yobuncane be-syntax, ungakwazi ukulungisa kahle lapho kwenziwa izenzo ukuze kuncishiswe umthelela.

Ngaphezu kwalokho, lokhu okuzenzakalelayo kunomthelela oqondile ku- ukusebenza kahle kanye nokukhiqizaAbasebenzi akudingeki bakhumbule ukuqala izinqubo ezijwayelekile, amaphutha abantu ayancishiswa, futhi amafasitela athwala umthwalo omncane asetshenziswa kangcono ukwenza imisebenzi enzima.

Kodwa-ke, ezindaweni zebhizinisi kuyanconywa Bhala phansi yonke imisebenzi ehleliwe kahle, gcina amakhophi agciniwe ama-crontabs, futhi ubuyekeze njalo ukuthi lokho okuchazwayo kusanengqondo.Ngokuhamba kwesikhathi, kulula ukuqoqa imisebenzi esiphelelwe yisikhathi eqhubeka nokusebenzisa izinsiza ngaphandle kokufaka isandla.

Ekugcineni, i-Cron ne-Crontab ziba uhlobo oluthile lwe- "ishejuli ezenzakalelayo" yesistimuUma zisetshenziswa ngokuhlakanipha, ziba yinto ebalulekile kokubili kumaseva aphansi kanye nengqalasizinda enkulu enemishini eminingi, futhi zikuvumela ukuthi ugcine isisekelo esiqinile sokwakha amanye amathuluzi okuqondisa noma okuqapha athuthukile.

Ngenxa yakho konke okungenhla, kusobala ukuthi Ukuhlela imisebenzi ku-Linux nge-Crontab kuseyindlela elula nenamandla kakhulu yokwenza uhlelo lwakho lube ngokuzenzakalelayoNgemigqa embalwa ebhalwe kahle, ungaphatha ama-backup, ukuhlanza, izibuyekezo, ukuqapha, kanye nezinqubo zebhizinisi ngaphandle kokuthinta inkinobho, inqobo nje uma uhlonipha imikhawulo yayo, uphatha izimvume, ulawula imvelo, futhi uhlela ngokuhlakanipha umthelela ekusebenzeni nasekuphepheni.