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运行shell脚本提示“语法错误: 未预期的文件结尾”
source link: https://blog.51cto.com/u_14045290/5811316
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运行shell脚本提示“语法错误: 未预期的文件结尾”
推荐 原创shenshushu 2022-10-31 21:36:10 博主文章分类：shell ©著作权
当时正在写一个小需求，shell脚本实现的功能是：通过 read 读入变量实现加减剩除等，而且要判断一个输入的2个变量是否为空，为空值则退出。输入的变量不是数字则退出。
自己编写的代码如下
#! /bin/bash
read -p "Ple input two num:" a b
if [ ${ #a } -le 0 ] && {
echo "this first number is null"
exit 1
}
if [ ${ #b } -le 0 ] && {
echo "this second number is null"
exit 1
}
expr $a +2 &>/dev/null
revecd_A=$?
expr $b +3 &>/dev/null
revecd_B=$?
if [ $revecd_A -ne 0 -o $revecd_B -ne 0 ];then
echo "ple input two number"
exit 1
fi
echo "a+b=$(($a+$b))"
echo "a-b=$(($a-$b))"
echo "a/b=$(($a/$b))"
echo "a%b=$(($a%$b))"
echo "a**b=$(($a**$b))"
read -p "Ple input two num:" a b
if [ ${ #a } -le 0 ] && {
echo "this first number is null"
exit 1
}
if [ ${ #b } -le 0 ] && {
echo "this second number is null"
exit 1
}
expr $a +2 &>/dev/null
revecd_A=$?
expr $b +3 &>/dev/null
revecd_B=$?
if [ $revecd_A -ne 0 -o $revecd_B -ne 0 ];then
echo "ple input two number"
exit 1
fi
echo "a+b=$(($a+$b))"
echo "a-b=$(($a-$b))"
echo "a/b=$(($a/$b))"
echo "a%b=$(($a%$b))"
echo "a**b=$(($a**$b))"
然后运行的时候提示错误
后来检查发现多了if
修改正确后代码如下
#! /bin/bash
read -p "Ple input two num:" a b
[ ${#a} -le 0 ] && {
echo "this first number is null"
exit 1
}
[ ${#b} -le 0 ] && {
echo "this second number is null"
exit 1
}
expr $a + 1 &>/dev/null
revecd_A=$?
expr $b + 1 &>/dev/null
revecd_B=$?
if [ $revecd_A -ne 0 -o $revecd_B -ne 0 ];then
echo "not unmber,ple input again"
exit 1
fi
echo "a+b=$(($a+$b))"
echo "a-b=$(($a-$b))"
echo "a/b=$(($a/$b))"
echo "a%b=$(($a%$b))"
echo "a**b=$(($a**$b))"
read -p "Ple input two num:" a b
[ ${#a} -le 0 ] && {
echo "this first number is null"
exit 1
}
[ ${#b} -le 0 ] && {
echo "this second number is null"
exit 1
}
expr $a + 1 &>/dev/null
revecd_A=$?
expr $b + 1 &>/dev/null
revecd_B=$?
if [ $revecd_A -ne 0 -o $revecd_B -ne 0 ];then
echo "not unmber,ple input again"
exit 1
fi
echo "a+b=$(($a+$b))"
echo "a-b=$(($a-$b))"
echo "a/b=$(($a/$b))"
echo "a%b=$(($a%$b))"
echo "a**b=$(($a**$b))"
验证结果：
反思总结：
if语句有相应的语法搭配：如
(1)
if [ command ].... ;then
符合条件执行语句
fi
（2）
if [command]
符合条件执行语句
else
否则执行什么
fi
（3）
if [command];then
符合条件执行语句
elif [command];then
如果符合这个条件，则执行语句
else
否则执行这个语句
fi
if [ command ].... ;then
符合条件执行语句
fi
（2）
if [command]
符合条件执行语句
else
否则执行什么
fi
（3）
if [command];then
符合条件执行语句
elif [command];then
如果符合这个条件，则执行语句
else
否则执行这个语句
fi
2.expr用于整数计算
如何expr 1+b，因为b不是整数，所以相加后运行结果就会出现错误，执行结果返回不是0.
根据执行成功返回结果是0进行判断 1和输入的传参变量是否是整数。
$? 获取执行上一个指令的执行状态返回值，0为成功，非零失败。
慢慢与你并肩
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