Indlela Yokubhala I-IF-Izitatimende ku-Bash-Script

Imiyalo, i-Syntax, nezibonelo

Nge-if-isitatimende, okuyinto uhlobo lwesitatimende esinemibandela, ungenza izenzo ezahlukene ngokuya ngezimo ezicacisiwe. Iphumelela yenza uhlelo lukwazi ukwenza izinqumo.

Isibonelo sendlela elula ye-if-isitatimende kungaba:

count = 5 uma [$ count == 5] bese u-echo "$ count" fi

Kulesi sibonelo, "inani" eliguquguqukayo lisetshenziselwa ukucacisa isimo esisetshenziswe njengengxenye ye-statement-statement. Ngaphambi kokuthi ngabe-isitatimende senziwa, i-variable "count" inikezwa inani "5". I-if-isitatimende sihlola ukuthi inani le "count" liyi "5". Uma kunjalo kunjalo isitatimende esiphakathi kwamagama angukhiye "ke" nethi "fi" senziwa, ngaphandle kwalokho noma yiziphi izitatimende ezilandela uma ngabe-isitatimende senziwa. Igama elingukhiye elithi "fi" lithi "uma" lihlelwa emuva. Ulimi lwe-bash scripting lusetshenziswa kulo mhlangano ukuze ubonise ukuphela kwesichazamazwi esiyinkimbinkimbi, okunjalo uma ngabe-isitatimende noma izikhombisi-zikhombo.

Isitatimende se-"echo" sishintsha impikiswano yaso, kulokhu, inani le-variable "count", kwiwindi lokugcina. Ukufakwa kwikhodi phakathi kwamagama angukhiye we-if-isitatimende sithuthukisa ukufunda kodwa akudingekile.

Uma unesimo lapho ikhodi kufanele ikhokhwe kuphela uma isimo singelona iqiniso, ungasebenzisa igama elingukhiye "okunye" ku-if-isitatimende, njengalesi sibonelo:

count = 5 uma [$ count == 5] bese u-"$ count" noma u-echo "ubala ayikho 5" fi

Uma isimo "$ count == 5" siyiqiniso, uhlelo lufaka inani lenani elithi "count", uma kungenjalo liprinta uchungechunge "inani aliyona 5".

Uma ufuna ukuhlukanisa phakathi kwezimo eziningi, ungasebenzisa igama elingukhiye elithi "elif", elisuselwa "kokunye uma", njengalesi sibonelo:

uma [$ count == 5] bese u-echo "ubala amahlanu" elif [$ count == 6] bese u-echo "ubala izintandathu" ngaphandle kokunye "akukho okunye okungenhla" fi

Uma "ukubalwa" kungu- "5", uhlelo luveza "ukubalwa kwezinhlanu". Uma "ukubalwa" akusikho "5" kodwa "6", uhlelo lufakela "inani lithandathu". Uma kungenjalo "5" noma "6", uhlelo lufaka "akukho okunye okungenhla".

Njengoba kungenzeka ukuthi ucabanga, ungaba nanoma iyiphi inombolo yezimpawu "elif". Isibonelo esinemibandela eminingi ye "elif" kungaba:

uma [$ count == 5] bese u-echo "ubala amahlanu" elif [$ count == 6] bese u-echo "ubala izintandathu" elif [$ count == 7] bese u-echo "ubala u-seven" elif [$ count = = 8] bese u-echo "ubala okungu-8" elif [$ count == 9] bese u-echo "ubala u-nine" ungabe usho "akukho okunye okungenhla" fi

Indlela ehambelanayo yokubhala izitatimende ezinjalo ngezimo eziningi yindlela yokwenza. Isebenza ngokufana ne-if-isitatimende enezimpawu eziningi "elif" kodwa isifinyelele kakhulu. Isibonelo, ikhodi engaphezulu ngenhla ingabhalwa kabusha nesitatimende esithi "icala" kanje:

icala "$ count" ku-5) u-echo "count count five" ;; 6) u-echo "count is six" ;; 7) u-echo "ubale uyisikhombisa" ;; 8) u-echo "count count eight" ;; 9) u-echo "ubala u-9" ;; *) echo "akukho okunye okungenhla" esac

Uma-izitatimende zivame ukusetshenziselwa ngaphakathi -izilophu noma izinkinobho ngenkathi kulesi sibonelo:

inani = 1 kwenziwe = 0 ngenkathi [$ count -le 9] ulala 1 ((count ++)) uma [$ count == 5] bese uqhubeka u-"$ count" echo eyenziwe iphelile

Ungase futhi ube nested uma izitatimende. Isithakazelo esilula kakhulu uma isitatimende singefomu: uma ... ke ... noma ... uma ... ke ... fi ... fi. Kodwa-ke, uma-isitatimende singasondeka ngokubunjwa okungaqondakali.

Bheka futhi ukuthi ungadlulisela kanjani izingxabano kwiskripthi se-bash , esibonisa ukuthi ungasebenzisa kanjani izimo zokucubungula ukucubungula imingcele edluliselwe emgqeni womyalo.

I-shell shell inikeza ezinye izinhlelo zokwakha, njenge -loops , ngenkathi-loops , nezinkulumo ze-arithmetic .