Uma uvilapha ukwenza imisebenzi ephindaphindayo kukhompuyutha yakho, i-Cron ikwenzela yona.
Yilokho i-athikili yesibili ochungechungeni lapho sisebenzisa uhlu lwalokho iSonto LamaKatolika elikubiza ngokuthi "izono ezibulalayo" njengezaba cYazi kabanzi mayelana nemiyalo nezinhlelo zomhlaba we-Linux. Kulokhu siqhubeka nokukhuluma ngokusetshenziswa kwe-cron ezoba usizo kakhulu kulabo abahlakulela ubuvila.
Njengoba siphila ezikhathini zabantu okulula ukubaphatha kabi, ake ngicacise, ngaphambi kokungena odabeni, ukuthi akuyona inhloso yami ukwenza inhlekisa ngezinkolelo zanoma ubani. Kunoma yikuphi, kuwukuzihlekisa. Ngachitha ingxenye enkulu yeminyaka yawo-XNUMX ngifunda ikhathekhizima ukuze ngemva kokuthatha iSidlo sami Sokuqala angibange ngisalubeka unyawo esontweni ngaphandle uma kunesidingo somndeni othile. Kufanele ngibuyise leso sikhathi ngandlela thize.
Ziyini i-cron ne-crontab?
Besishilo ukuthi i-cron i-daemon, okungukuthi uhlelo olusebenza ngemuva ngaphandle kokungenelela komsebenzisi. Ngibheka ulwazi olwengeziwe lwalesi sihloko, ngithole ukuthi ukuhumusha i-daemon (Indlela amasistimu we-Unix nokuphuma kokunye abiza ngayo lolu hlobo lohlelo) njenge-daemon iphutha elisabalelekodwa angizukuyilungisa. Sikhuluma ngezono, kumele okungenani kube nedimoni elilodwa.
Umsebenzi we-cron ukwenza, ngesikhathi esishiwo ngaphambili, umsebenzi othile. Isikhathi esiningi kungenxa yezidingo zesistimu, nakuba abasebenzisi bangabonisa abanye ngokuhlela ifayela lombhalo elaziwa ngokuthi i-crontab.
Kokuthunyelwe kwangaphambilini besishilo ukuthi imiyalo yokwakha i-crontab yilena:
crontab –e kumsebenzisi ozenzakalelayo
O
crontab –u nombre_de_usuario nganoma yimuphi omunye.
I-Crontab iyifayela lombhalo elinikeza iziyalezo ze-Cron zokuthi ukwenze nini nokuthi ukwenze nini.
Mayelana nokusebenzisa i-cron nge-crontab
Ukwakha i-crontab yethu kufanele sicabangele lokhu okulandelayo:
- Kusetshenziswa umugqa owodwa kumsebenzi ngamunye.
- Idethi nesikhathi sokwenziwa komsebenzi kufanele kukhonjiswe. Uma kwenzeka kuwumsebenzi odinga i-periodicity. Isibonelo, njalo ngoLwesithathu ngo-5 ekuseni, amanye amapharamitha athathelwa indawo yizinkanyezi (*).
- Uma ufuna ukunikeza inani elingaphezu kwelilodwa lepharamitha enikeziwe, inani ngalinye kufanele lihlukaniswe ngekhoma.
- Amapharamitha ahlukaniswa nesikhala.
- Uhla lwemibhalo lapho kukhona isiqalisi somyalo kufanele kwaziwe
Ngokwesibonelo, uma sifuna ukuthi ikhompuyutha yezingane zethu icishwe nsuku zonke ngo-20:XNUMX p.m., umyalo uzoba
0 20 * * * /sbin/shutdown
Uma kwenzeka sifuna ukuvala shaqa kube ngamaSonto kuphela, siyawuguqulela umyalelo
0 20 * * 0 /sbin/shutdown
Kukhona izinqamuleli ezisisindisa ekutheni sibhale wonke amapharamitha. Kunjalo:
- @ngehora: Faka umyalo ngehora ezimpondweni.
- @nsuku zonke: Qalisa umyalo ekuqaleni kosuku ngalunye.
- @masonto onke: Qalisa umyalo ekuqaleni kosuku lokuqala lweviki.
- @nyangazonke: Qalisa umyalo ekuqaleni kosuku lokuqala lwenyanga ngayinye.
- @ngonyaka: Yenza umyalo ngomzuzu wokuqala wonyaka.
Ezinye izibonelo zokusebenzisa lo myalo yilezi:
@daily /bin/sh /ruta_al_script/nombre_del_script.sh sebenzisa iskripthi se-Bash.
@hourly /bin/python3 /ruta_al_script/nombre_del_script.py sebenzisa iskripthi se-python njalo ngehora.
Kuzo zonke izimo imibhalo kufanele ibe nezimvume zokuqalisa.
Ezibonelweni esizibonile, akubonisiwe umyalo kuphela, kodwa nendlela lapho okuphunyeleliswayo kutholakala khona. Sizosebenza nalezi zinkomba:
- /umgqomo: Iqukethe zonke izinhlelo zokusebenza ezidingekayo ekusebenzeni kohlelo.
- /sbin: Nazi izinhlelo zokusebenza ezidingwa ngumsebenzisi wempande ukuze aphathe isistimu.
- / ekhaya: Lapho izinhlelo zokusebenza zomsebenzisi ngamunye zigcinwa khona.
- /usr: Izinhlelo zokusebenza namafayela afakwe abasebenzisi agcinwe lapha. Afaka amafayela anamagama nemisebenzi eshiwo kulolu hlu.
Esihlokweni esilandelayo sizobona indlela yokuthuthukisa ukubhala kwe-crontab namanye amathuluzi wokuzenzakalelayo atholakalayo weLinux.