Question

for (( c=0; c<$i; c++ )); do
if [[ "$aTitle" == "${bookTitle[$c]}" ]]; then 
if [[ "$aAuthor" == "${author[$c]}" ]]; then    
found=true
fi
fi
done

echo $found

嗨，我对shell编程很新，有人能告诉我为什么在运行这段代码时出现这个错误？非常感谢。 bookTitle＆amp; author是一个字符串数组 aTitle＆amp; aAuthor是用户输入

function add_new_book
{
echo "1) add_new_book"

found=false

echo -n "Title: "
read aTitle
echo -n "Author: "
read aAuthor

for (( c=0; c<$i; c++ )); do
    if [[ "$aTitle" == "${bookTitle[$c]}" ]]; then 

        if [[ "$aAuthor" == "${author[$c]}" ]]; then    

            found=true

        fi

    fi
done

echo $found
}

#author[$i]=$aAut}

./menu.sh: line 43: syntax error near unexpected token `done'
./menu.sh: line 43: `   done'

Answer 1

标准posix shell的for loop错误！它不是C / C ++，它是shell，这是通常的方法：

for c in $(seq 0 $i); do
    ...
done

以及以下构造：

typeset -i i END
for ((i=0;i<END;++i)); do echo $i; done

是特定于bash的，以下不会出错：

#!/bin/bash

function add_new_book() {
    echo "1) add_new_book"

    found=false

    echo -n "Title: "
    read aTitle
    echo -n "Author: "
    read aAuthor

    # declare c and END as integers
    typeset -i c END
    let END=5 # use END instead of $i if $i is not defined!
    for ((c=0;c<i;++c)); do

        if [[ "$aTitle" == "${bookTitle[$c]}" ]]; then 

            if [[ "$aAuthor" == "${author[$c]}" ]]; then    

                found=true

            fi

        fi
    done

    echo $found
}

add_new_book

所以我猜你可能一直试图用/bin/sh而不是/bin/bash来运行该示例，这可能是dash或bsh之类的另一个shell。此外，您不应在for循环条件中使用$i，而i不能使用$。

N.B。：在我给出的脚本中，仍然存在错误：$i未在脚本的上下文中定义！

Answer 2

此示例脚本可能会对您有所帮助。

bookTitle="linux,c,c++,java"
author="dony,jhone,stuart,mohan"

function add_new_book()
{
    IFS=', ' 
    read -a bookTitle <<< "$bookTitle"
    read -a author <<< "$author"

    echo "1) add_new_book"

    found=false

    echo -n "Title: "
    read aTitle
    echo -n "Author: "
    read aAuthor


    for index in "${!bookTitle[@]}"
    do  
        if [[ "$aTitle" == "${bookTitle[index]}" ]]
        then    

            if [[ "$aAuthor" == "${author[index]}" ]]
            then    
                    found=true
            fi
        fi
    done

    echo $found
}

Bash if else语句错误

2 个答案: