Fumana ukuba ngaba ifayile ikhona okanye ayikho kwinkqubo yethu

Njengoko sisazi iqokobhe lisivumela ukuba sibe nolawulo olugqithisileyo Yenkqubo yethu iphela, ngaphandle koburhabaxa bayo kunye nendlela yamandulo kwabaninzi xa kuthelekiswa nonxibelelwano lwangoku lwegraphical. Kodwa kufuneka kukhunjulwe ukuba yeyona ndlela isebenzayo, nangona ifuna ulwazi lobuchwephesha. Ingxaki nge-GUI ayisiyiyo kuphela ukuba inezithintelo ngokuthelekiswa nesiphelo, kodwa ikwakhona ukuba uqhuba umaleko ongezelelweyo wemizobo etya izixhobo ezininzi ezingayi kumiselwa umsebenzi wokugqibela.

Besisazisa ezinye Izifundo ezincinci Olunye lwamathuba anokufumaneka kwimiyalelo elula. Le yenye yazo, kwaye njengoko ubona, zizenzo ezilula ezinokuba luncedo olukhulu kwiimeko ezininzi. Ewe, kule meko ngokuthe ngqo siza kujonga ukuba kwenzeka njani ngemiyalelo embalwa elula xa sinokubona ukuba ifayile okanye uninzi lwazo lukhona kwinkqubo yethu okanye hayi. Amanyathelo oku kulandelayo:

[ -f /etc/httpd ] && echo "Existe" || echo "No existe"

Njengoko ubona, sisebenzise amabinzana ovavanyo ngayo. Ngokusisiseko into esiyenzileyo kumzekelo, nangona ungayifaka enye indawo ngeendlela ezininzi zokugcina is syntax, kukuvavanya ukuba / etc / httpd ikhona kwinkqubo yethu okanye hayi. Kwimeko esele ikho, kuba-- f ukhetho lubuyisela ixabiso eliyinyani ukuba likhona, umyalezo "okhoyo" uya kuboniswa ngombulelo kusetyenziso lomyalelo we-echo. Ngelixa kungenjalo iya kubonisa "ayikho". Ilula njengaleyo…

Unokubambela -f for ezinye iindlela zokhetho, njenge -e, eya kuthi ibuyise ixabiso eliyinyani ukuba ikhona, kodwa ingavavanyi ukuba yifayile eqhelekileyo. Nge -r into efanayo iya kwenzeka, kodwa kule meko ivavanya ukuba yifayile efundekayo. Ukubona ukuba kuyabhalwa ukusetyenziswa -w, -x ukubona ukuba iyaphunyezwa, kunye -d ukubona ukuba sisikhombisi ... Amathuba maninzi. Ungasebenzisa umlinganiswa! ukukhanyela izenzo. Umzekelo, ukujonga ukuba akukho / njl / ifayile yovavanyo:

[ ! -f /etc/prueba ] && echo "No existe"