Leli fayela le-crontab lisetshenziselwa ukutshela u-cron ukuthi yiziphi izitatimende okufanele zisebenze.
Ku ingxenye yesithathu zalolu chungechunge lwezihloko lapho sisebenzisa izono eziyisikhombisa ezibulalayo njengezaba ukwazi amathuluzi nezinhlelo zeLinux, sizophawula kabanzi ngokucushwa kwe-cron futhi sizokhuluma ngenye indlela
I-cron wuhlelo oluzimele lodwa lokuqhuba imisebenzi yokulungisa uhlelo njalo. Imisebenzi icaciswe kufayela lombhalo elaziwa ngokuthi i-crontab.
Mayelana ne-cron ne-anachron
Ezihlokweni ezedlule sixoxe ngesakhiwo semiyalelo okufanele siyinikeze i-cron. Manje sizobona indlela elula yokubhala ifayela le-crontab.
Umyalo crontab –e yakha ifayela le-crontab elicishe lingenalutho. Kunemigqa embalwa kuphela eyandulelwa uphawu lwephawundi (#). Lesi sibonakaliso sibonisa ukuthi zingamazwana futhi akufanele zizanywe ukubulawa. Singazisusa noma sizishiye.
Kufanele siqale ngokwengeza le migqa:
SHELL=/bin/bash: Icacisa ukuthi igobolondo elizosetshenziswa ukusebenzisa imiyalo lithi Bash. Igobolondo liyitolika lomyalo elivumela umsebenzisi ukuthi afinyelele izinsiza zesistimu.
MAILTO=una_dirección_de_mail: Ekusakazweni kohlangothi lweseva kuvamile ukucacisa ikheli le-imeyili ukuze abalawuli bathole imibiko yeziphazamisi. Kungakho kuyinketho i-cron esebenzisa ngokuzenzakalelayo ukuyithumela. Kumakhompuyutha edeskithophu lelo kheli alilungiselelwanga ukuze silenze ngalokhu kuhlukahluka.
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin: Lokhu kusisindisa ekubeni sicacise indlela eya kokusebenzisekayo kumyalo ngamunye.
i-anachron
I-Cron iyaziwa kakhulu ngamathuluzi e-automation, kodwa ine-drawback yokuthi, uma ikhompuyutha icishiwe noma imisiwe, umsebenzi awenziwa kuze kube yilapho ubuyela osukwini olumisiwe. I-Anacron. Ngokuphambene nalokho, kuyaqikelela ukuthi lapho iseshini iqalwa kabusha, imisebenzi esalindile iyenziwa. Uhlelo luthola ukuthi umyalelo wagcina nini ukwenziwa nokuthi utshelwe kangaki ukuthi kufanele usetshenziswe. Uhlu lwemisebenzi elindile lurekhodwa efayeleni lombhalo elibizwa kuleli cala i-anacrontab. Ngokungafani ne-cron ne-crontab, usuku lusethwa ngokusetha usuku, ukubambezeleka ngamaminithi, isihlonzi somsebenzi kanye nomyalo wokukhipha.
Ngomsebenzi ngamunye, u-Anacron uhlola ukuthi lo msebenzi wenziwe yini ezinsukwini zokugcina n, lapho u-n kuyinkathi eshiwo kulowo msebenzi. Uma kungenjalo, i-Anacron isebenzisa umyalo wegobolondo lomsebenzi, ngemva kokulinda inombolo yamaminithi ecaciswe njengepharamitha yokubambezeleka.
Ngemva kokuba umyalo usuqedile, i-Anacron ifaka idethi efayeleni lesitembu sesikhathi esikhethekile salowo msebenzi, ukuze wazi ukuthi uzoyiqalisa nini futhi. Idethi kuphela esetshenziselwa izibalo zesikhathi. Isikhathi asisetshenziswa.
Singathola i-anacron ngaphansi kwaleli gama noma njengengxenye yenye iphakheji ebizwa ngokuthi i-cronie kumakhosombe wokusatshalaliswa kweLinux okuyinhloko.
Amapharamitha e-Anacron
-F: Yenza umsebenzi kungakhathaliseki ukuthi idethi ekhonjiwe.
-noma: Ishintsha idethi yemisebenzi ibe yile yamanje, kodwa ayiwenzi.
-s: Imisa ukuthi umsebenzi uzoqalwa kuphela lapho owandulele usuqediwe.
-n: Qalisa umsebenzi kungakhathaliseki ukuthi usuku luni. Vula ipharamitha -s.
-d: Ayisebenzi ngemuva futhi amaphutha akhiqizwa njengomlayezo wephutha ojwayelekile. Umphumela womsebenzi uthunyelwa ngeposi. Esimeni sesistimu yedeskithophu, ikheli le-imeyili liyalungiswa njengoba kukhonjisiwe ngenhla.
-q: Ivimbela imilayezo yephutha evamile ukuthi ingakhiqizi. Isetshenziswa kanyekanye -d.
-t: Uma kwenzeka ufuna ukusebenzisa uhlu lwemisebenzi oluhlukile kunalolo oludalwe ngokuzenzakalelayo, le parameter itshela i-anacron ukuthi iyiphi okufanele isebenzise.
-T: Hlola uhlu lwemisebenzi ukuze ubone ukuthi lulungiswe kahle yini. Uma kungenjalo, ikhiqiza umlayezo wephutha.
-S Gcina izitembu zesikhathi kuhla lwemibhalo olucacisiwe ukuze lusetshenziswe yi-anacron.
Esihlokweni esilandelayo sizobona indlela yokumisa kahle i-anacrontab