General Syntax of Bash IF ELIF ELSE Below is the general syntax ofIFELIFandELSEin bash: ifCONDITION-TO-TEST;then CODE-TO-EXECUTE-1 elifNEXT-CONDITION-TO-TEST;then CODE-TO-EXECUTE-2 elifNEXT-CONDITION-TO-TEST;then CODE-TO-EXECUTE-2 ...
Bash scripting is a powerful tool for automating tasks in the Linux environment. One of the key elements of any programming or scripting language is conditional logic, and in Bash, this is achieved through if statements. In a bash script,if statementchecks whether a condition is true or not....
Hint: Refer to the previous chapter onbash strings You may discuss your solution in the Community: Practice Exercise in Bash Basics Series #7: If Else Statements If you are following the Bash Basics series on It’s FOSS, you can submit and discuss the answers to the exercise at the end ...
在 Linux 环境的 Bash 脚本中，条件逻辑的核心工具是 if 语句。它用于检查一个条件是否为真，并据此决定执行相应的代码块。Bash 支持多种 if 语句形式，包括基本的 If、If-else、If-elif-else、嵌套 If 以及 Case 语句。逻辑运算符如大于、小于等，用于组合多个条件。例如，比较数字的简单 if 语句...
Checking the exit status using an ‘if’ statement in Bash Using a “if” statement and the “$?” variable, we can determine whether a command or script has executed successfully. Which holds the exit status of the most recent command executed, the syntax of the “if” statement for dete...
Using else if statement in bash You can use an elif (else-if) statement whenever you want to test more than one expression (condition) at the same time. For example, the followingage.shbash script takes your age as an argument and will output a meaningful message that corresponds to your...
In the above example, we used the double square brackets ([[ ... ]]) that indicated a conditional expression in Bash, and it allowed for more advanced comparisons and pattern matching. In this case, we checked if the value of bool_var was equal to the true. To check equality, we use...
如果if语句后放入一个不能工作的命令,则状态码为非0,且bash shell会跳过then后面的语句。 [22:43:53 root@libin3 libin]# vim shell21 /bin/bash #this is result error if libin then echo "this is error" fi if date then echo "this is success" ...
If statement and else statement could be nested in bash. The keyword “fi” indicates the end of the inner if statement and all if statement should end with the keyword “fi”. The “if then elif then else fi” example mentioned in above can be converted to the nested if as shown belo...
多数情况下[ ]和[[]]是可以通用的,单中括号 [ ],bash 的内部命令,[和test是等同的。双中括号[[ ]],[[是 bash 程序语言的关键字。并不是一个命令,[[ ]] 结构比[ ]结构更加通用。 [ ] 和 [[]]区别 [ ]中可用的比较运算符只有==和!=,可用于字符串比较的,不可用于整数比较,整数比较只能使用-eq...