Yintoni / dev / null kwaye ingakunceda njani?

Ukuba sele sinemibono yesikhokelo somthi we-GNU / Linux, kuya kufuneka okungenani siqhelane ne / dev / ireferensi, eyiyo apho zonke iifayile zinxulumene izixhobo zekhompyutha. Ukuba sijonga kulawulo / dev / Siza kubona "ifayile" ebizwa null, kodwa ukuba sifuna ukuyivula ukuze ibone umxholo wayo, le nkqubo iya kusixelela ukuba ayinakwenzeka kuba ayisiyomxholo uqhelekileyo. Ndilivalile igama lefayile kuba, njengoko nonke niyazi ngeLinux yonke into (izixhobo zekhompyutha kunye nesoftware) imelwe njengefayile.

Sesiphi isixhobo esihambelana / dev / null esihambelana naso?

Ngeenjongo ezibonakalayo, khawufane ucinge umgqomo wenkunkuma, umngxunya ongenasiphelo okanye indawo engaphandle yokuphosa kuyo nantoni na ngaphandle kokuyifumana (nokuba bazama kangakanani na abafana baseNASA).

Kodwa ukuba sele ndinemiyalelo efana ne-rm, kutheni ndifuna into entsha ukuba ndiyicime?

Kuba indlela esebenza ngayo "imingxunya emnyama" yahluke ngokupheleleyo: ungaya njani ngaphezulu kokukhutshelwa komgangatho kwimpazamo kumyalelo ngaphakathi kweskripthi esisebenza ngexesha lokubaleka? Kulapho i / dev / null ingena khona.

Makhe siyibone ngomzekelo.

Senze ifayile ebizwa ngokuba ziimvavanyo ezinomtya "Molo weHlabathi". Ukuba sifuna ukubonisa umxholo wale fayile kumgca wokuyalela, sinokuyenza ngale ndlela ilandelayo:

umsebenzisi @ ilaptop: ~ $ uvavanyo lwekati
Molo Lizwe

Ukuba le fayile ibingekho okanye kwathiwa igama njengovavanyo (ngee 's ekugqibeleni), singafumana le mpazamo ilandelayo kwikhonsoli:

umsebenzisi @ ilaptop: ~ $ iimvavanyo zekati
ikati: iimvavanyo: Ifayile okanye ulawulo alukho

Yintoni esinokuyenza ukuphepha umyalezo wemposiso? Ewe, thumela nje imveliso yomyalelo, kwimeko yempazamo, uye kwi "trash can", Oko kukuthi / dev / null

Siyichaza njani ukuba iya kuba kwimeko yeempazamo? Apha ufaka igalelo eliqhelekileyo, ukuphuma, kunye neempazamo zenkqubo: STDIN, STDOUT, kunye STDERR (enokuthi ithathe indawo ye0, 1, kunye no-2 ngokwahlukeneyo). Ngale ndlela, ukuba sibeka ...

umsebenzisi @ ilaptop: ~ $ iimvavanyo zekati 2> / dev / null
umsebenzisi @ ilaptop: ~ $

… Siza kubona ukuba umyalezo wempazamo awuzukuveliswa kwikhonsoli.

Kuya kufuneka ulumke kuba is syntax ibalulekile: phakathi kwabalinganiswa 2 kunye> akubikho sithuba. Ngaphandle koko, iya kunika oku kulandelayo:

umsebenzisi @ ilaptop: ~ $ iimvavanyo zekati 2> / dev / null
ikati: iimvavanyo: Ifayile okanye ulawulo alukho
ikati: 2: Ifayile okanye ulawulo alukho

Ngokuchaseneyo, indawo phakathi> kunye / dev / null ayizukuchaphazela kakubi iziphumo.

Sinokuphinda sisebenzise ukuhanjiswa kwakhona kwempazamo, umzekelo, ukufaka iimpazamo kwifayile yelog ngolu hlobo lulandelayo:

umsebenzisi @ ilaptop: ~ $ cat iimvavanyo 2> err.log

Elinye ityala elinomdla kukuqokelelwa kweziphumo kwenye ifayile ukuba impazamo ayenzeki, esingayibeka kuyo:

umsebenzisi @ ilaptop: ~ $ uvavanyo lwekati 1> iziphumo_iziphumo 2> err.log

Okokugqibela, kubalulekile ukubeka ibinzana elithi "> / dev / null 2> & 1" apho iziphumo ezisemgangathweni kunye neziphumo zempazamo zidityanisiwe, sizithumela kwakhona ukuze kungabikho meko ikhoyo.