line 6: [: 192.168.26.233: unary operator expected

本文探讨了Shell脚本中使用if语句进行条件判断时遇到的问题,并给出了两种有效的解决方案:一是通过双引号将变量包裹起来;二是采用双括号[[ ]]的方式进行条件判断。

学习shell的时候出了下面一个问题困扰了我一会

line 6: [: 192.168.26.233: unary operator expected

经过定位就是如下一行

if [ $lianjie = $hosts ]


[root@zw-test-db ~]# sh aaa
aaa: line 6: [: 192.168.26.233: unary operator expected

报错的原因是:变量 lianjie 的值出现为空的情况,那么就if语句就变成了if [  = $hosts ],这不是一个合法的条件。

为了避免出现这种情况,我们可以用双[[]]或者变量加上双引号都可以避免这个问题,如下

if [ "$lianjie" = "$hosts" ]
if [[ $lianjie = $hosts ]]


[root@yfw ~]# cd /opt/openfire/enterprise/spark/Spark [root@yfw Spark]# # 推荐使用 openfire 用户身份运行(更安全) [root@yfw Spark]# su - openfire -s /bin/bash ✅ JAVA_HOME: /usr/lib/jvm/java-11-openjdk ✅ Maven home: /opt/maven ✅ Java version: openjdk version "11.0.13" 2021-10-19 LTS [openfire@yfw ~]$ [openfire@yfw ~]$ # 切换到 Spark 目录 [openfire@yfw ~]$ cd /opt/openfire/enterprise/spark/Spark [openfire@yfw Spark]$ [openfire@yfw Spark]$ # 设置 DISPLAY 环境变量(通常为 :0) [openfire@yfw Spark]$ export DISPLAY=:0 [openfire@yfw Spark]$ [openfire@yfw Spark]$ # 启动 Spark [openfire@yfw Spark]$ ./Spark ./Spark: line 384: basename: command not found ./Spark: line 385: dirname: command not found ./Spark: line 400: dirname: command not found ./Spark: line 401: basename: command not found ./Spark: line 81: expr: command not found ./Spark: line 82: expr: command not found ./Spark: line 96: awk: command not found ./Spark: line 97: cp: command not found ./Spark: line 100: sed: command not found ./Spark: line 103: chmod: command not found ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected Error: Could not find or load main class install4j.org.jivesoftware.launcher.Startup [openfire@yfw Spark]$
最新发布
10-31
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
红包 添加红包
表情包 插入表情
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值