for变量名in取值列表do命令 done 语法二: for ((expr1;expr2;expr3));do 命令列表 done 实例: #提前准备好用户的文件[root@VM_0_10_centos shellScript]#vi username.txttest01 test02 test03 test04 test05 test06#vi example.sh#!/bin/bashread -p"请输入用户密码:"PASSWDforUNAMEin`cat username.t...
until [$RETURN-eq 0 ];doecho"hadoop is no sign-in"sleep5who|grep"hadoop"&>/dev/null RETURN=$?doneecho"hadoop is log in"Example2是对命令的执行状态进行判断,这个是取出命令执行状态的返回值进行条件判断 Example4:#!/bin/bashdeclare-isum=0declare-i i=1while((i<=100));doletsum+=i#sum+...
<statement list>可以包含任何有效的 PowerShell 語句,包括 break 和continue 關鍵詞。 例如,如果while變數尚未建立,或$val變數已建立並初始化為0,下列$val語句會顯示數位1到3。 PowerShell 複製 while($val -ne 3) { $val++ Write-Host $val } 在此範例中,條件 ($val 不等於 3)為 true,而 $val ...
bash shell if-statement while-loop m3u 我正在编写一个脚本来解析m3u文件。目标是检索变量标记和url。我用这个文件做了测试。 #!/bin/bash echo "name,tvg-id,tvg-name,tvg-country,group-title,languages,url" while IFS= read -r line; do tags_detect="$(echo "$line" | grep -Eo '^#EXTINF:')...
hdc shell命令是否支持schema uri模拟跳转 是否可以通过ApplicationContext启动UIAbility 使用hdc命令安装release HAP包到设备时上报“INSTALL_FAILED_APP_SOURCE_NOT_TRUSTED”错误 如何查询应用包的名称、供应商、版本号、版本文本、安装时间、更新时间描述信息 如何安装打包出来的App包(通过什么命令安装) 如何判断应...
In the above script, the user is asked to press theq/Qkey on the keyboard to exit the loop. The functionget_keyis getting the input from the user and comparing it. In the infinite while loop, first, theechostatement will execute after that, the function is called to monitor the input...
echo “Invalid user input.”– This command prints the error message in the terminal when the condition in theifstatement evaluates to false. exit 1– This line stops the script with an exit code of1to indicate an error. fi– This specifies the end of theifstatement. ...
This is a very simple example, where theloopexecutes untilNUMBERis not greater than10and prints theecho statement. Along withwhilewe will use thereadcommand to read the contents of a file line by line. Below is the syntax of howwhileandreadcommands are combined. Now there are different ways...
In the above script, it checks the value of the variable “x”, if it reaches 10 just jumps out of the loop using break statement. Awk Continue statement Continue statement skips over the rest of the loop body causing the next cycle around the loop to begin immediately. ...
在React中,useEffect是一个React Hook,用于处理副作用操作。副作用操作包括但不限于数据获取、订阅事件、手动操作DOM等。而while循环是一种循环结构,用于重复执行一段代码直到条...