所以,bash script是只能在bash环境下运行的script。 如何运行bash script 学习一门新语言最开始最想知道的必然是如何运行了。当然运行前得检查环境。 $echo$SHELL/bin/bash 如果已经是bash,那就没问题了,说明已经在bash环境了。如果不是bash,那么为了告诉shell,“请用bash来理解我的script”,我们
# code to be executed if condition is false fi ``` 在这个语法中,`[ condition ]` 是if语句中的条件表达式。如果条件表达式的结果为真(非零),则执行`then`块中的代码。否则,执行`else`块中的代码。`fi`是if语句的结束标记。 下面是一个简单的例子,演示if语句的用法: ```bash #!/bin/bash num1=1...
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if else 语法格式: if condition then command1 command2 ... else command fi if else-if else语法格式: if condition1 then command1 elif condition2 then command2 else commandN fi #if else语句经常与test命令结合适用,如下所示: #!/bin/bash num1=$[2*3] num2=$[1+5] if test $[num1] -...
bash script 执行方式区别 三种执行方式:source、.、sh 小数点和sh是在开启一个子进程上执行,脚本里的变量和操作不会传到父进程 source直接在父进程中执行 例如配置生效用source ~/.bashrc而不用sh ~/.bashrc 分支 判断符号[] 中括号内的每个组件都需要空格键分隔,常用于if..then..fi中...
fi# 逻辑或if[ condition1 ] || [ condition2 ] fiif[[ condition1 || condition2 ]] fi 6. 最大公约数 #!/bin/bash# 最大公约数ARGS=2 E_BADARGS=65# 参数检查if[ $# -ne "$ARGS" ]then echo"Usage: `basename $0` first-number second-number"exit $E_BADARGS ...
If a statement is proven to be true, then a condition would run. This functionality enables us to determine the circumstances under which a certain piece of code shall be executed. In bash, we start the conditional with an if statement and end it with fi (if spelled backward). Here is...
/bin/bashn=10if[$((n%2))==0]thenecho"The number is even."elseecho"The number is odd."fi Copy Output: The number is even Copy As you can see, we’ve enclosed a part of the condition within double brackets. That’s because we need the modulus operation to be performed before ...
#!/bin/bash#NUMBER=$1#if [ $NUMBER -gt 20 ] # gt(>) lt(<) eq(=) -ne(!=) #then # echo "Given number: $NUMBER is greater than 20" #else # echo "Given number : $NUMBER is less than 20" #fiNUMBER=$1if[ $NUMBER -...
Incorrect use of a test operator in a Conditional Statement like using -z instead of -n in a if condition Incorrect use of an Arithmetic operator like multiplying instead of diving a number Incorrect condition to exit from a Bash Loop like when using a while loop instead of an until loop ...