Indlela yokusebenzisa "bc" Calculator kwi Scripts

Iprogram ye-Linux bc ingasetyenziswa njengendlela yokubala ideskithophu elula okanye njengelwimi lokubhala isicwangciso semathematika. Kulula nje ngokuba kubiza umyalelo we- bc ngokusebenzisa i-terminal.

Ngaphandle kwe-bc nesebenzi, igobolondo yeBash inikeza ezinye iindlela ezimbalwa zokwenza imisebenzi ye-arithmetic .

Qaphela: Inkqubo ye-bc ikwabizwa ngokuba yi-calculator eyisiseko okanye i-calculator bench.

bc I-Syntax yoLawulo

I- syntax yomyalelo we-bc iyafana nolimi lweprogram yeC, kwaye iindidi zabaqhubi zixhaswa, njengokongezwa, ukukhupha, kunye nokunciphisa, kunye nokunye.

Ezi zizitshixo ezahlukeneyo ezikhoyo nge-bc umyalelo:

• -h, --help: Iprint le ndlela yokusetyenziswa kwaye iphume.
• -i, - engasebenzi: Imodi yokusebenzisana yamaqela.
• -l, - imathlib: Sebenzisa i-routine yezibalo ezichazwe ngaphambili.
• -q, - quiet: Ngaba ayiprinta ibhanna yokuqala.
• -s, i-standard: Izakhiwo ezingaqhelekanga ze-bc zephutha.
• -w, - uqaphele: Uxwayisa malunga nezakhiwo ezingaqhelekanga ze-bc.
• -v, --version: Ulwazi lweenguqulelo kunye nokuphuma.

Khangela le Bc Manual Manual ukuze uthole iinkcukacha ezingakumbi malunga nendlela onokusebenzisa ngayo i-calculator eyisiseko.

bc Umzekelo Umyalelo

I-calculator eyisiseko ingasetyenziselwa kwisigxina ngokungena kwi- bc , emva koko ungabhala iintetho eziqhelekileyo ezifana nale:

4 + 3

... ukufumana umphumo onje:

7

Xa uqhuba uchungechunge lwezibalo ngokuphindaphindiweyo, kuyaqondakala ukusebenzisa i-calculator bc njengenxalenye yeskripthi. Ifom elula kakhulu yeskripthi esinokubheka into efana nale:

#! / bin / bash echo '6.5 / 2.7' | bc

Umgca wokuqala ngumendo owenzayo osebenza kule script.

Umgca wesibini uqulethe imiyalelo emibini. Umyalelo we- echo udala umtya oqulethe imathematika ebhalwe kwiingcaphuno ezifanayo (6.5 ehlulwe ngu-2.7, kulo mzekelo). Umqhubi wombhobho (|) udlula lo mtya njengengxabano kwiprogram ye-bc. Umphumo weprogram ye-bc ke uboniswe kumgca wokulawula.

Ukuze usebenzise le script, vula ifasitela yesigxina uze ulandele kwirejista apho i-script ifumaneka khona. Siza kuthatha ifayile yeskripthi ibizwa ngokuba yi-bc_script.sh . Qiniseka ukuba ifayile isebenza ngokusebenzisa umyalelo we- chmod :

chmod 755 bc_script.sh

Emva koko uza kungena:

./bc_script.sh

Isiphumo siza kuba zilandelayo:

2

Ukuze ubonise iindawo ezi-3 zokugqibela ukusuka kwimpendulo yangempela yi-2.407407 ..., sebenzisa isitatimende esikalini ngaphakathi komtya okhishwe ngamagama athile:

#! / bin / bash echo 'scale = 3; 6.5 / 2.7 '| bc

Ukufundeka kangcono, umgca wokubala ungabhalwa kwakhona kwiimizila emininzi. Ukuze uphule umgca womyalelo kwimigca emininzi ungayifaka umva wokugqibela emva komgca:

u-echo 'scale = 3; var1 = 6.5 / 2.7; var1 '\ | bc

Ukubandakanya iziphakamiso zomgca womyalelo kwiibalo zakho ze-bc, kufuneka utshintshe iicatshulwa enye kwiingcaphuno eziphindwe kabini ukwenzela ukuba impawu zeparameter yelayini yomyalelo zitshintshwe ngegobol yeBash:

bhala "isikali = 3; var1 = 6.5 / 2.7; var2 = 14 * var1; var2 * = $ 1; var2" \ | bc

Umxholo wokuqala womgca womyalelo ufikeleleka usebenzisa uguquko "$ 1", ingxabano yesibini isebenzisa "i-$ 2", njl.

Ngoku ungabhala imisebenzi yakho ye-arithmetic ngokwezikhethi zeBash ezihlukeneyo uze ubabize kwezinye iincwadi zeempendulo.

Umzekelo, ukuba i-script1 iqulethe:

#! / bin / bash echo "scale = 3; var1 = 6.5 / 2.7; var2 = 14 * var1; var2 * = $ 1; var2" \ | bc

... kunye ne script2 iqulethe

#! / bin / bash var0 = "100" echo "var0: $ var0" umsebenzi fun1 {echo "scale = 3; var1 = 10; var2 = var1 * $ var0; var2" \ | bc} fres = $ (fun1) echo "fres:" $ fres var10 = $ (./ script1 ii-fres); phendula "var10:" $ var10;

... ke ukuqhuba i-script2 kuya kucela i-script1 isebenzisa i-variable fres $ efakwe kwiscript2 njengeparitha.