Bash：意外标记“then”附近的语法错误

Bash: Syntax error near unexpected token `then'

提问by user3291870

the error is at line 21...

错误在第 21 行...

if [ $weight1 -gt $weight2 ];
    then echo "Weight 2 should be greater than Weight 1."
else
    if [ $weight1 -ge 20 ] && [ $weight1 -le 39 ];
        then echo "Weight 1 is bike."
    else 
        echo "Weight 1 is either bicycle, car, van or lorry."
    fi
fi

回答by Малъ Скрылевъ

I done\'t see the issue, on my tests thenkeyword is worked for your case, anyway some noted on your code:

我没有看到这个问题，我的测试then关键字适用于您的情况，无论如何，您的代码中有一些注释：

1. Put thenon the line of ifoperator:

   if [ $weight1 -ge 20 ] && [ $weight1 -le 39 ]; then
   

2. Enclose your variables into quotes:

   if [ "$weight1" -ge 20 ] && [ "$weight1" -le 39 ]; then
   

3. I recommend to use -akey, instead to two calls to [app:

   if [ "$weight1" -ge 20 -a "$weight1" -le 39 ]; then
   

1. 放在运算符then的行上if：

   if [ $weight1 -ge 20 ] && [ $weight1 -le 39 ]; then
   

2. 将变量括在引号中：

   if [ "$weight1" -ge 20 ] && [ "$weight1" -le 39 ]; then
   

3. 我建议使用-a密钥，而不是两次调用[应用程序：

   if [ "$weight1" -ge 20 -a "$weight1" -le 39 ]; then
   

NOTE:The error Syntax error near unexpected token 'then'can rise up mostly in a few cases:

注意：Syntax error near unexpected token 'then'在少数情况下，错误可能会增加：

1. When you specify thenkeyword outside of ifcase:

   weight1=21
       then echo "Weight 1 is bike."
   else
       echo "Weight 1 is either bicycle, car, van or lorry."
   fi
   

2. when youve specified thentwice:

   if [ "$weight1" -ge 20 -a "$weight1" -le 39 ]; then
   then echo "Weight 1 is bike."
   

3. when you've put thento improper place, for example, after the elseoperator:

   else
   then
       echo "Weight 1 is either bicycle, car, van or lorry."
   fi
   

1. 当您then在if大小写之外指定关键字时：

   weight1=21
       then echo "Weight 1 is bike."
   else
       echo "Weight 1 is either bicycle, car, van or lorry."
   fi
   

2. 当您指定then两次时：

   if [ "$weight1" -ge 20 -a "$weight1" -le 39 ]; then
   then echo "Weight 1 is bike."
   

3. 当你放在then不合适的地方时，例如，在else操作员之后：

   else
   then
       echo "Weight 1 is either bicycle, car, van or lorry."
   fi
   

回答by MLSC

just

只是

chmod +x test.sh

first line: add #!/bin/bash

第一行：添加 #!/bin/bash

then do:

然后做：

./test.sh

It is working whithout problem

它可以正常工作