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...
case expression in pattern1) statements ;; pattern2) statements ...
The function of if-else in shell script is an important asset for shell programmers. It is the best tool to use when you need to execute a set of statements based on pre-defined conditions. The if-else block is one, if not the most essential part of conditional programming. By regulatin...
‘Else if’, or ‘elif’, adds more flexibility to your conditional statements. It allows you to check multiple conditions in a single ‘if’ statement. The script executes the first condition that is true and ignores the rest. Here’s an example of an ‘elif’ statement: a=10if[$a-gt...
每一条命令;不管是内置的,shell 函数,还是外部的,当它退出时,都会返回一个小的整数值给引用它的程序,这就是大家所熟知的程序的退出状态.在 shell 下执行进程是,有很多方式可取用程序的退出状态. 以管理来说,退出状态为 0 表示”成功”,也就是,程序执行完成且为遭遇到任何问题.其他任何的退出退出状态都为失败...
Conditions in bash scripting (if statements) Shell中判断语句if中-z至-d的意思 - sunny_2015 - 博客园 https://www.cnblogs.com/coffy/p/5748292.html Conditions in bash scripting (if statements) - Linux Academy Blog https://linuxacademy.com/blog/linux/conditions-in-bash-scripting-if-statements/...
Using Nested If Statements A nested if statement is an if statement inside a clause of another if statement. Nothing prevents multiple levels of if statement in a shell script and in Bash. if first-test-commands; then if second-level-test-commands; then consequent-commands; else second-level...
do-while循环是一种后测试循环,即先执行循环体,再判断条件是否满足。而"If"条件是一种条件语句,用于根据条件的真假来执行不同的代码块。 当结合使用do-while循环和"If"条件时,可以实...
Like many other languages, PowerShell has statements for conditionally executing code in your scripts. One of those statements is the If statement. Today we will take a deep dive into one of the most fundamental commands in PowerShell. Note The original version of this article appeared on the...
Naturally, this is not optimal. On top of this, involving more advanced shell features such as loops and conditions, we might end up with some complex syntax. 3. Conditional Statements As we’ve already seen, basicif–elsestatements conform to thePOSIXstandard: ...