Question

我写了一个使用if-elif结构的小脚本。由于某种原因它只是不起作用。错误代码：

./lab4.sh: line 9: syntax error near unexpected token `elif'
./lab4.sh: line 9: `elif [ $number -eq 2 ] then func2'

我的实际代码：

#!/bin/bash
#ask the user for a number between 1 and 3
#create some functions, write out the function number
echo "Enter a number between 1 and 3: "
read number

#which function should be called?
if [ $number -eq 1 ] then func1
elif [ $number -eq 2 ] then func2
elif [ $number -eq 3 ] then func3 fi

function func1 {
    echo "This message was displayed from the first function."
}

function func2 {
    echo "This message was displayed from the second function."
}

function func3 {
    echo "This message was displayed from the third function."
}

Answer 1

您必须在shell语句（;，if，then，elif ...）之前返回新行或使用fi。

您还必须在使用之前声明您的功能。

#!/bin/bash
#ask the user for a number between 1 and 3
#create some functions, write out the function number
echo "Enter a number between 1 and 3: "
read number

function func1 {
    echo "This message was displayed from the first function."
}

function func2 {
    echo "This message was displayed from the second function."
}

function func3 {
    echo "This message was displayed from the third function."
}

#which function should be called?
if [ $number -eq 1 ]; then func1
elif [ $number -eq 2 ]; then func2
elif [ $number -eq 3 ]; then func3; fi

Answer 2

对于这样的多个if/elif，有时更容易使用case语句，例如：

func1() { echo "func1"; }
func2() { echo "func2"; }
func3() { echo "func3"; }

while read -r -p 'Enter a number between 1 and 3:>' number
do
    case "$number" in
        1) func1 ; break ;;
        2) func2 ; break ;;
        3) func3 ; break ;;
        q) exit;;
        *) echo "Wrong input" >&2;; #error message
    esac
done
echo "end of loop"

评论：请勿使用function关键字。它是 bashism ，定义shell函数的可移植方式是

funcname() {
}

它也有点短......：）

elif的语法错误

2 个答案: