Shell scripting, specifically Bash scripting, is a great way to automate repetitive or tedious tasks on your systems. Why type when you can schedule and run ...
In Linux,whileloopsare essential tools for automating repetitive tasks and controlling the flow of programs.These loops enable us to execute a block of code repeatedly, provided that a specified condition is true. Moreover,whileloops are versatile in that we can include user input as the specifie...
Shell脚本中的whilegetopts用法小结 getpots是Shell命令行参数解析工具,旨在从ShellScript的命令行当中解析参数。getopts被Shell程序用来分析位置参数,option包含需要被识别的选项字符,如果这里的字符后面跟着一个冒号,表明该字符选项需要一个参数,其参数需要以空格分隔。冒号和问号不能被用作选项字符。ge ...
Shell编程中,有几种常见的循环结构,包括for循环、while循环和until循环,总的来说,循环在Shell编程中扮演着至关重要的角色,它们使得自动化任务变得更加容易,提高了效率,并且可以处理各种各样的编程需求。 1.for循环 for循环允许你对一组元素(如数组中的元素、文件中的行、命令的输出等)进行迭代。 最常用的for循环 ...
shell脚本forloops&whileloops题解 一、for loops for 变量名 in 列表;do 循环体 done 执行机制: 依次将列表中的元素赋值给“变量名”; 每次赋值后即执行一次循环体; 直 到列表中的元素耗尽,循环结束 列表生成方式: (1) 直接给出列表 (2) 整数列表:...
Shell编程中循环命令用于特定条件下决定某些语句重复执行的控制方式,有三种常用的循环语句:for、while和until。while循环和for循环属于“当型循环”,而until属于“直到型循环”。循环控制符:break和continue控制流程转向。 参考:《Linux 与unix shell 编程指南》 ...
In Bash scripting, the while loop functions by repeating a set of instructions as long as the specified condition is true.
...WHILE [ > ] WHILE expression LOOP statements END LOOP [ label ]; 只要条件表达式为真,其块内的语句就会被循环执行...[ > ] FOR record_or_row IN query LOOP statements END LOOP [ label ]; 这是另外一种形式的FOR循环,在该循环中可以遍历命令的结果并操作相应的数据...
Shell while 循环while 循环用于不断执行一系列命令,也用于从输入文件中读取数据;命令通常为测试条件。其格式为:while command do Statement(s) to be executed if command is true done命令执行完毕,控制返回循环顶部,从头开始直至测试条件为假。以下是一个基本的 while 循环,测试条件是:如果 COUNTER 小于5,那么...
Example 1: Infinite While loop in a shell script An infinite While loop means your script will run the loop commands non-stop. Infinite While loops never stop running and this occurs when the condition always turns out to be “True.” ...