Shell if...elif...fi 語句

if...elif...fi 語句是提前一個級別的控制語句,形式出幾個條件,允許 Shell 作出正確的決定。

語法

if [ expression 1 ] then Statement(s) to be executed if expression 1 is true elif [ expression 2 ] then Statement(s) to be executed if expression 2 is true elif [ expression 3 ] then Statement(s) to be executed if expression 3 is true else Statement(s) to be executed if no expression is true fi

這段代碼沒有什麼特別的。這僅僅是一個系列,if 語句每一個語句else子句的一部分。下面語句是執行的基礎上的真實情況,如果條件不爲 ture,則執行else塊。

例子:

#!/bin/sh a=10 b=20 if [ $a == $b ] then echo "a is equal to b" elif [ $a -gt $b ] then echo "a is greater than b" elif [ $a -lt $b ] then echo "a is less than b" else echo "None of the condition met" fi

這將產生以下結果:

a is less than b