这个密码有什么问题

图书id必须唯一。
主题代码只能是UNIX或C

我有以下错误

/test.sh:第13行:unix:找不到命令
./test.sh:第92行:语法错误:意外的文件结尾

    echo -n "Enter Book Accession number: "
        read Book_accession_number

        declare -a var_id
        declare -i i =0

        subject()
        {
        echo -n "Enter Subject code:"

        read Subject_code

        if ("$Subject_code" !=  "unix")
        then
{
        if ("$Subject_code"  !=  "c")
        then
{
        echo "please enter unix or c"
        subject
        }
        fi
}
        fi


        subject
        Book()
        {
        echo -n "Enter Book ID:"
        read Book_id
        echo -n "Enter Book Accession number: "
        read Book_accession_number

        declare -a var_id
        declare -i i =0






        while(j -ne i)
        {
        j++
        if(var_id[i]==Book_id)
        then
        {
        echo "please enter a unique id"
        Book
}
        fi


        }

        Book


        echo -n "Enter Author Name:"
        read Author_name

        echo -n "Enter Year of Publication:"

        read YOP

        echo -n "Enter Title of Book:"

        read TOB

        echo -n  "Enter Publisher's name:"

        read PUB_Name;

        echo -n "Enter Price: "
        read Price