Chidziwitso ku Bash

Momwe Mungakwirire Zolemba ku Bash Script

Ngakhale Bash ndi chinenero cholembera, chiri ndi mphamvu zokwanira za chinenero cholumikizira cholinga. Izi zikuphatikizapo ntchito za masamu. Pali njira zingapo zomwe mungagwiritsire ntchito poyesa masvomerezo a mawu. Mwina lowerengeka kwambiri ndi lamulo lololeza. Mwachitsanzo

lolani "m = 4 * 1024"

adzawerengera 4 nthawi 1024 ndikupereka zotsatira zake ku "m".

Mukhoza kusindikiza zotsatirazo powonjezera mawu akuti:

lolani "m = 4 * 1024" echo $ m

Mukhoza kuyesa izi kuchokera ku mzere wa lamulo mwa kulowa mu code zotsatirazi:

lolani "m = 4 * 1024"; Tengerani $ m

Mukhozanso kupanga fayilo yomwe ili ndi malamulo a Bash, pameneyi muyenera kuwonjezera mzere pamwamba pa fayilo yomwe imalongosola pulogalamu yomwe ikuyenera kuti ikhale yoyenera. Mwachitsanzo:

#! / bin / bash let "m = 4 * 1024" likhale $ m

kuganiza kuti Bash amachititsa kukhala / bin / bash . Muyeneranso kukhazikitsa zilolezo za fayilo yanuyi kuti ichitidwe. Poganiza kuti dzina la fayilo ndi script1.sh , mukhoza kukhazikitsa zilolezo kuti fayilo iwonongeke ndi lamulo:

chmod 777 script1.sh

Zitatha izi mukhoza kuzichita ndi lamulo:

./script1.sh

Ntchito zomwe zilipo zokhudzana ndi masamu zimakhala zofanana ndi zomwe zili m'zinenero zoyenera monga Java ndi C. Kuwonjezera pa kuchulukitsa, monga momwe tafotokozera pamwambapa, mumagwiritsa ntchito:

lolani "m = a + 7"

kapena kuchotsa:

lolani "m = a - 7"

kapena kugawa:

lolani "m = a / 2"

kapena modulo (otsalira pambuyo pogawidwa kwazitali):

lolani "m =% 100"

Pamene opaleshoni imagwiritsidwa ntchito mofanana ndi zomwe zotsatirazo zimapatsidwa mungagwiritse ntchito machitidwe ovomerezeka a masewera omwe amagwira ntchito, omwe amatchedwanso ogwira ntchito ogwira ntchito. Mwachitsanzo, kwawonjezera, tili ndi:

lolani "m + = 15"

zomwe ziri zofanana ndi "m = m + 15". Kwa kuchotsa ife tiri:

lolani "m - = 3"

omwe ali ofanana ndi "m = m - 3". Kwa magawano tili:

lolani "m / = 5"

omwe ali ofanana ndi "m = m / 5". Ndipo kwa modulo, tili:

lolani "m% = 10"

omwe ali ofanana ndi "m = m% 10".

Kuonjezerapo, mungagwiritse ntchito owonjezera operekera:

lolani "m ++"

ndilofanana ndi "m = m + 1". Ndipo

lolani "m--"

ndilofanana ndi "m = m - 1".

Ndiyeno pali opareshoni a "funso-coloni" omwe amatha kubwezeretsa chimodzi mwa zikhulupiliro ziwiri malingana ndi momwe zinthu zilili zoona kapena zabodza. Mwachitsanzo

lolani "k = (m <9)? 0: 1"

Gawo la dzanja lamanja la ndondomekoyi limaphatikizapo "0" ngati "m" yosasintha ndi yocheperapo ndi 9. Apo ayi, imawunika ku 1. Izi zikutanthawuza kuti "k" yowonjezera imapatsidwa "0" ngati "m" ili yochepa kuposa 9 ndi "1" mwinamwake.

Maonekedwe onse a funsolo-owonetsa makononi ndi awa:

chikhalidwe? Chofunika-ngati-chowonadi: mtengo-ngati-wabodza

Chizindikiro cha Arithmetic ku Bash

Woyendetsa ntchitoyo amangogwira ntchito yokhudzana ndi masamu. Chifukwa cha masamu omwe mungagwiritse ntchito pogwiritsa ntchito GNU bc calculator monga momwe tawonera m'nkhaniyi:

lembani "32.0 + 1.4" | bc

Ogwiritsa ntchito "pipi" "|" amapereka mawu a masamu "32.0 + 1.4" kwa bc calculator, yomwe imabweretsanso nambala yeniyeni. Lamulo lolozera limalongosola zotsatirazo kuti zitheke.

Alternative Syntax ya Arithmetic

Zibwezeretsedwe (zotsatizana za m'mbuyo) zingagwiritsidwe ntchito poyesa ndondomeko ya masamu monga mwachitsanzo ichi:

lembani "expr $ m + 18`

Izi zidzawonjezera 18 ku mtengo wa variable "m" ndikusindikiza zotsatira.

Kupatsa chiwerengero cha compute kwa variable mungagwiritse ntchito chizindikiro chofanana popanda malo ozungulira:

m = `expr $ m + 18`

Njira inanso yowerengera malemba a masamu ndi kugwiritsa ntchito mau ovomerezeka awiri. Mwachitsanzo:

((m * = 4))

Izi zidzasokoneza phindu la kusintha kwa "m".

Kuwonjezera pa kuyeza kwa masamu, chipolopolo cha Bash chimapanga mapulogalamu ena, monga loops , nthawi-malupu , conditionals , ndi ntchito ndi magulu aang'ono .