在bash 脚本中,if 语句检查一个条件是否为真。如果是,shell 执行与 If 语句相关的代码块。如果语句不为真,则 shell 跳过 If 语句块的末尾并继续执行。 在本指南中,我们将解释如何在 bash 脚本中使用 if 语句。在 bash shell 脚本中,If 语句可以以 If、If- else、If- If- else、netsted If 和 case 的...
#!/bin/bashcase$1in"hello")echo"Hello, I am fine,thank you!";;"")echo"你必须要输入一个...
User input validation is crucial in shell scripting to ensure that the input provided by the user is valid and can be processed correctly. If-else statements can be used to validate user input and prompt the user to enter valid input if necessary. Here’s an example of a script that valid...
An alternative to if-else statements in shell scripting is the case statement. The case statement allows you to match a value against multiple patterns and execute different blocks of code based on the match. Here’s an example: case$varin1)echo"Variable is 1.";;2)echo"Variable is 2."...
Scripting 1. Introduction As the ubiquitous Linux shell,Bashhas its own features and scripting syntax, which upgrade those of the regularshshell. On the other hand, most shells agree on how the basicconditional expressionswork at the logical and syntactic levels. ...
[ is a shellbuiltin$typetesttestis a shellbuiltin 又说这是叫 builtin,坑爹,不过常用命令如 cd、echo 都是这样的。 但是说双方括号是「关键词」,关键词就是 bash 自己内建的语法分析: $type[[ [[isa shell keyword 就因为这是关键词,所以被双方括号包围的代码都有另外一种意义,&&、||、>和<</CODE...
shell的基本语句(for循环,while循环,嵌套循环,if 的多重循环,case语句) 1.for循环(遍历) 练习1:检测当前172.25.254网段主机的状态 练习2:写一个10秒的倒计时 练习3:写一个用户自定义分秒的倒计时 2.while循环 练习1:批量创建用户,并非交互式修改用户密码 3.嵌套循环 练习:打印9*9乘法表 4.if-else 循环 ...
Bash Scripting and Conditional Statements To fully grasp the power of ‘else if’ in bash scripting, it’s essential to understand the fundamentals of bash scripting, conditional statements, and flow control. What is Bash Scripting? Bash (Bourne Again SHell) is a command-line interpreter, or s...
How to work of if else condition in shell scripting? Interactive Usage of CSH If Statements Question: My Solaris 10 csh implementation of the "if" statement seems suspicious or I may not have a clear understanding of it. The latter is likely considering my situation. ...
If this, then that else something else. Doesn't make sense? It will after you learn about the if-else statements in bash shell scripting. Bash supports if-else statements so that you can use logical reasoning in your shell scripts.