- Indlela i-crond daemon esebenza ngayo nokuthi imisebenzi iphathwa kanjani kusetshenziswa ifayela le-crontab.
- Ukuhlelwa kwemisho okuningiliziwe kanye nokusetshenziswa kwezinhlamvu ezikhethekile ukuhlela ukwenziwa okunembile.
- Ukusetshenziswa kwezikripthi zokusekelayo nge-TAR kanye nokwenza ngokuzenzakalelayo ukulungiswa kwesistimu.
- Ezinye izindlela zesimanje ezifana nama-timer e-systemd namathuluzi ezithombe zokuphatha izinqubo.
Kungakhathaliseki ukuthi usanda kushintshela ku-Linux noma ubulokhu uphatha iseva yakho isikhathi esithile, cishe usuqaphele ukuthi eminye imisebenzi inzima kakhulu ukuyenza ngesandla. Kusukela ekuhlanzeni amafayela esikhashana kuya ekuqinisekiseni ukuthi idatha yakho iphephile ngama-backup, ukwenza lezi zinqubo ngokuzenzakalela kubalulekile ekugwemeni ukukhungatheka nokuvimbela ukunganaki okulula ekuqedeni umsebenzi wenyanga yonke.
Ukuze kuxazululwe lokhu, izinhlelo ezifana ne-UNIX zinethuluzi elidumile elibizwa ngokuthi i-Cron. Ngokuyisisekelo, kufana newashi le-alamu lemiyalo evula izikripthi noma izinhlelo zokusebenza ngesikhathi esiqondile osichazile, isebenza ngemuva ngenkathi uphuza ikhofi noma ukhohlwe ngokuphelele ukuthi umsebenzi ukhona.
Iyini ngempela i-Cron futhi ihamba kanjani?
Uma sikhuluma nge-Cron, empeleni sibhekisela ku- daemon ebizwa ngokuthi i-crond . Ezweni le-Linux, i-daemon imane nje inqubo esebenza ngemuva, ngaphandle kwesixhumi esibonakalayo somsebenzisi, kusukela ngesikhathi uhlelo luqala ukusebenza. Umsebenzi wayo uyadina kodwa ubalulekile: njalo ngeminithi ihlola amafayela okucushwa ukuze ibone ukuthi ikhona yini imisebenzi ye-cron ehleliwe ehambisana nesikhathi samanje nosuku.
Ukuze konke kusebenze kahle, kubalulekile ukuthi iwashi lesistimu lisethwe kahle. Uma isikhathi noma indawo yesikhathi ingalungile, ama-backup akho azosebenza ngesikhathi esingafanele. Ngakho-ke, kunconywa ukusebenzisa umyalo othi `timedatectl` ukuqinisekisa ukuthi ukuvumelanisa namaseva e-NTP kulungile, ukuqinisekisa ukuthi uhlelo alunawo ukungafani kwesikhathi.
Ifayela le-Crontab: Lapho kwenzeka khona umlingo
Uma i-Cron iyinjini, i- crontab iyimephu yemiyalelo . Iyifayela lombhalo lapho sibhala khona ukuthi sifuna ukuyisebenzisa nini nokuthi nini. Ngokuthakazelisayo, akukho ifayela elilodwa kuphela; uhlelo lune-crontab yomhlaba wonke ku-/etc/crontab, kodwa umsebenzisi ngamunye angaba ne- eyakhe , okuvumela abantu abahlukene ukuhlela imisebenzi yabo ngaphandle kokudinga amalungelo okuphatha ngaso sonke isikhathi.
Ukuze siphathe le misebenzi, sisebenzisa umyalo othi `crontab -e` ukuhlela, `crontab -l` ukufaka ohlwini okusebenzayo, kanye nothi `crontab -r` uma sifuna ukususa konke bese siqala phansi. Kuyindlela ehlanzekile kakhulu yokuhlela ukugcinwa kwesistimu ngaphandle kokuthinta amafayela abalulekile e-kernel.
Ukuhlahlela i-syntax ye-Cron
Ukuze uhlele umsebenzi, kufanele ulandele uhlelo oluqinile lwezinkambu zesikhathi ezinhlanu olulandelwa umyalo. Uchungechunge luthi: umzuzu, ihora, usuku lwenyanga, inyanga, kanye nosuku lwesonto . Isibonelo, uma sifaka u-0 19 * * 0, sitshela uhlelo ukuthi lusebenze ngo-7 ntambama njalo ngeSonto.
Ukuze senze izimpilo zethu zibe lula, kukhona izinhlamvu ezikhethekile okusinika ukulawula okuphelele. Inkanyezi (*) isho ukuthi "njalo" noma "noma yiliphi inani," kuyilapho i-slash (/) isetshenziselwa ukuchaza izikhawu, njengokuthi */10 ukusebenzisa okuthile njalo ngemizuzu eyishumi. I-hyphen (-) ichaza amabanga kanye ne-comma (,) ikuvumela ukuthi ubhale amanani athile. Ngaphezu kwalokho, kukhona izinqamuleli ezichazwe ngaphambilini njenge-@daily, @weekly noma i-@reboot, okwenza kube lula ukubhala ezimweni ezivame kakhulu.
Ukudala uhlelo lwakho lokuqala lokusekelayo
Enye yezinhlelo zokusebenza eziwusizo kakhulu ukusekela ngokulondoloza idatha. Kulokhu, ithuluzi le-TAR liyindlela efanelekile yokukhetha . Singakha iskripthi se-Bash esipakisha amafayela ethu, sinikeze usuku lwamanje igama lefayela, futhi, okubaluleke kakhulu, singafaki amafolda angadingekile njenge-cache noma udoti ukuze ukusekela ngokulondoloza kungabi ama-gigabytes e-junk.
Uma iskripthi sesidaliwe (isibonelo, ku-/usr/local/bin/mybackup) futhi izimvume zokusebenzisa sezinikeziwe nge-chmod +x , mane nje ungeze umugqa ku-root crontab. Ngale ndlela, iseva izokwenza isipele ngokuzenzakalelayo, futhi ungahlela ngisho iskripthi ukuthi sisuse ngokuzenzakalelayo izipele ezindala kunamasonto amabili ukuze ugweme ukugcwalisa i-hard drive.
Ukuphathwa okuthuthukisiwe kanye nezindlela eziphelele
Iphutha elivame kakhulu phakathi kwabaqalayo ukusebenzisa izindlela ezihlobene ezikriphthini zabo. I-Cron isebenza endaweni elinganiselwe kakhulu futhi ayazi indawo yakho, ngakho-ke kufanele usebenzise njalo izindlela eziphelele (njenge-/home/user/script.sh esikhundleni se-./script.sh). Ngaphandle kwalokho, umyalo uzohluleka buthule, futhi uzoba nesimanga esingathandeki lapho udinga ukubuyisa idatha yakho.
Ukuze ugweme ukuhamba ungaboni, kubalulekile qondisa kabusha okukhiphayo ku-logUkusebenzisa i-opharetha >>> /var/log/backup.log 2>&1Singagcina kokubili impumelelo kanye nokwehluleka kufayela. Ngaleyo ndlela, uma kukhona okungahambi kahle, sidinga kuphela ukubheka ifayela lelogi ukuze sazi kahle ukuthi kwenzekeni ngaphandle kokuqagela.
Umthelela ekusebenzeni kahle kanye nemikhuba emihle kakhulu
Akunconywa ukulayisha ngokweqile uhlelo ngemisebenzi eqhutshwa njalo ngomzuzwana, njengoba lokhu kungabangela ukwanda kokusetshenziswa kwe-CPU ne-RAM . Indlela ehlakaniphile kakhulu ukuhlela izinqubo ezidinga izinsiza eziningi, njengokuvuselelwa kwedatha noma ama-backups amakhulu, ngezikhathi zasekuseni noma ngezikhathi ezingezona ezesikhathi esimatasa ukuze ugweme ukuthinta abasebenzisi.
Ukuze kuvinjelwe umsebenzi owodwa ukuthi ungahambisani nomunye uma owokuqala uthatha isikhathi eside kunokulindelekile, kunconywa ukusebenzisa i-flock , okuvimbela ukwenziwa ngasikhathi sinye kweskripthi esifanayo. Ngaphezu kwalokho, ukuze kuvinjelwe ukuthi ubani ongasebenzisa i-Cron, umphathi angalungiselela amafayela e -cron.allow kanye ne-cron.deny , aqinisekise ukuthi abasebenzi abagunyaziwe kuphela abangahlela imisebenzi kuseva.
Ezinye izindlela zesimanje: Ama-Systemd Timers nokuningi
Nakuba i-Cron iyisistimu yakudala, izinhlelo zesimanje zisebenzisa ama-systemd timers . Lezi zinamandla kakhulu ngoba zikuvumela ukuthi uphathe ukuncika, uphathe amaphutha ngempumelelo, futhi wenze imisebenzi ngokusekelwe kwimicimbi yesistimu (njengokuqala) hhayi iwashi nje kuphela. Zihlelwe kusetshenziswa amafayela e-.timer kanye ne-.service ku-/etc/systemd/system/.
Kulabo abangakhululekile nge-terminal, kunezinketho zezithombe ezifana ne-KCron (ye-KDE) noma amathuluzi asekelwe kuwebhu njenge-Webmin. Kwezinye izinhlelo zokusebenza, njenge-macOS, kusetshenziswa i-launchd , enikeza ukuhlanganiswa okujulile kakhulu ne-Apple ecosystem, okuvumela imisebenzi ehlulekile ukuthi iqalwe kabusha ngokuzenzakalelayo.
Amanye amacala okusetshenziswa komhlaba wangempela kumaseva
Ngaphandle kokwenza ama-backups, i-Cron iyithuluzi elifanele lokugcina uhlelo lwakho luhlanzekile . Ungahlela imisebenzi yokususa ama-log amadala masonto onke noma uqale kabusha izinsizakalo ezivame ukuphahlazeka. Kubalulekile futhi ekuvumelaniseni idatha usebenzisa i-rsync phakathi kwemishini ehlukene, ukuqinisekisa ukuthi ulwazi luyaphindaphindwa ngaphandle kokungenelela komuntu.
Ezindaweni zewebhu, isetshenziswa njalo ukuthumela ama-imeyili amaningi , ukukhiqiza imibiko yokuthengisa yansuku zonke, noma ukuvuselela i-cache yekhasi. Ngokuyisisekelo, noma yisiphi isenzo esiphindaphindwayo nesibikezelwayo singadluliselwa ku-Cron ukuze kuthuthukiswe umkhiqizo womlawuli.
Ukwazi ukwenza izinto ngokuzenzakalela ku-Linux kukuvumela ukuthi uguqule iseva ephethwe ngesandla ibe umshini ozimele futhi osebenzayo. Ngokuhlanganisa ukusetshenziswa kwezikripthi ze-Bash, ukunemba kwe-crontab, kanye nokuqapha amalogi, ungaqinisekisa ukuthi ukugcinwa, ukuphepha, kanye nobuqotho bedatha kuphathwa ngokuzenzakalelayo, kukhulula isikhathi futhi kunciphisa kakhulu umkhawulo wamaphutha abantu ekuphathweni kwengqalasizinda.