1. How to use in if condition in shell script? To use an if condition in a shell script, you can follow the basic syntax of an if statement. Here’s an example: if[condition];then# code to execute if condition is truefi For example, to check if a file exists: ...
Shell 支持任意数目的分支，当分支比较多时，可以使用if elif else 结构，它的格式为：ifcondition1then...
1、if语法格式 1.1 if格式 if condition; then commands; fi 1.2 else if 和 else if c...
To understand if-else in shell scripts, we need to break down the working of the conditional function. Let us have a look at the syntax of the if-else condition block. if [condition] then statement1 else statement2 fi Copy Here we have four keywords, namely if, then, else and fi....
--格式如下:if[ condition ]thencommandsfi 第一个方括号之后和第二个方括号之前必须加上一个空格,否则就会报错。test命令可以判断三类条件:(1)数值比较(2)字符串比较(3)文件比较。 1.1 数值比较 下面测试脚本中,第一个条件使用-gt,value1是否大于value2。 第二个条件使用-eq 测试value1 是否与value2相等。
The line, if test $1 -gt 0 , test to see if first command line argument($1) is greater than 0. If it is true(0) then test will return 0 and output will printed as 5 number is positive but for -45 argument there is no output because our condition is not true(0) (no -45 ...
[ condition ] && action; #如果condition条件为真,则执行action; [ condition ] || action; #如果condition条件为假,则执行action; 二、循环控制语句 1、for循环 for var in list; do action; done 其中list可以是一个字符串、序列或数组等。 采用c语言方式的for循环语句: ...
PowerShell $condition=$trueif($condition) {Write-Output"The condition was true"} if語句所做的第一件事就是計算括號中的運算式。 如果計算結果為$true,則會在大括號中執行scriptblock。 如果值是$false,則會略過該腳本區塊。 在上一個範例中,if語句只是評估$condition變數。 它是$true,並且會在腳本塊內...
shell逻辑控制语句之if if语句结构 用法1: if CONDITION; then statement statement fi CONDITION条件的写法: COMMAND [ expression ] expression表达式: 数学表达式 字符表达式 文件目录表达式 数学表达式: [ number1 -eq number2 ]等于 [ number1 -ne number2 ]不等于...
$ if [ $(echo TEST) ]; then echo CONDITION; fi CONDITION Let’s now try the same example without the proper spacing: $ if [ $(echo TEST)]; then echo CONDITION; fi bash: [: missing `]' $ if [$(echo TEST) ]; then echo CONDITION; fi bash: [TEST: command not found $ if [...