在Bash 脚本中遇到错误 -bash: syntax error near unexpected token 'then' 通常意味着在 then 关键字的使用上存在语法问题。以下是根据你的提示,对可能的问题和解决方案的分点解答: 确认then关键字在脚本中的位置: then 关键字应该紧跟在 if 或elif 条件语句之后,中间不应该有任何其他命令或字符。 bash if [ ...
因为if condition,如果条件为真,就会进入if块区域内执行命令。 如果你是对$?结果很执着的读者,可以去看朱双印的博客原文。 场景一:判断变量是否为空 假如有变量 如上表所示,变量值非空时 condition 为真。使用上述方法判断变量值是否为空时,[ ] 与 [[ ]] 没有区别。 我们可以使用”!”进行取反,使得变量值...
'Else if'in bash scripting, often written as'elif', is used to check multiple conditions in your code. It is used with the syntax,if [firstStatement]; then... elif [secondCondition]; then... else. It’s a powerful tool that allows your scripts to make decisions based on various scen...
Conditions in bash scripting (if statements) - Linux Academy Blog https://linuxacademy.com/blog/linux/conditions-in-bash-scripting-if-statements/ Table of conditions The following table list the condition possibilities for both the single- and the double-bracket syntax. Save a single exception, th...
Bash条件判断(condition-test)是用来控制程序的流程,它可以添加一些条件,根据不同的条件做出不同的反应。Bash条件判断中一般可以分为:条件测试算式、条件操作符、逻辑操作符;其中单词语法(word-based syntax)是Bash条件判断的基础;即使用if,test等命令用来判断条件。 条件测试算式 条件测试算式是Bash条件判断的基础,它将...
bash 中的条件语句，基础就是 Test 。 if 先来个实例： x=5; if [ $x = 5 ]; then e...
a condition that is false. The syntax of the if statement in Bash is: if first-test-commands; then consequent-commands; [elif more-test-commands; then more-consequents;] [else alternate-consequents;] fi Tests commands in the bash if statement, and bash elif clauses, are executed in ...
A basic if statement commands that if a particular condition is true, then only execute a given set of actions. If it is not true, then do not execute those actions. If statement is based on the following format: Syntax of If statement ...
]; then echo "JAIL is set to a non-empty string"fiif [ -n "${JAIL+set}" ]; then echo "JAIL is set, possibly to the empty string"fiif [ -n "${JAIL-unset}" ]; then echo "JAIL is either unset or set to a non-empty string"fidone## syntax 1 ##if [[ -z "$va...
Syntax: if [ conditions ] then commands fi 1. 2. 3. 4. Example: 让我们比较两个数字并找出它们的关系: read x read y if [ $x -gt $y ] then echo X is greater than Y elif [ $x -lt $y ] then echo X is less than Y