所谓的 loop 就是 script 中的一段在一定条件下反复执行的代码。 bash shell 中常用的 loop 有如下三种: * for * while * until for loop 是从一个清单列表中读进变量值,并"依次"的循环执行 do 到 done 之间的命令行。 例: for var in one two three four five do echo
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 scripts in a hands-free manner? One of the many scripting constructs is the loop. A loop is a section of code that picks up data ...
在今后的编程实践中,希望你能灵活运用while循环,为解决各种自动化任务提供高效的解决方案。while循环的灵活性和强大功能,使其成为Shell脚本编程中不可或缺的工具。 继续探索Shell编程的其他强大功能,不断提升你的编程能力,期待你在Shell脚本编写中取得更多成就!让while循环成为你编程工具箱中的一把利器,助你在Shell编程...
每循环一次,就将列表中的下一个值赋给变量。 in 列表是可选的,如果不用它,for 循环使用命令行的位置参数。 举例顺序输出列表中的数字 forloopin12345doecho"The value is: $loop"done 顺序输出字符串 forstrin'This is a string'doecho$strdone 输出结果 This is a string 显示 家目录下的sh文件: forfil...
/bin/bashx=1while[$x-le5]doecho"Welcome $x times"x=$(($x+1))done Here is a sample shell code to calculate factorial using while loop: #!/bin/bashcounter=$1factorial=1while[$counter-gt0]dofactorial=$(($factorial*$counter))counter=$(($counter-1))doneecho$factorial...
echo "Loop completed." Let’s discuss the instructions in thescript.shfile: #!/bin/bash– this line is known as theshebang, and its purpose is to instruct the system to execute this script using the Bash shell read -p “Number of iterations: ” iterations_count– thereadcommand prompts...
问Bash中的While-loop子壳困境ENbash中的变量
bash shell while语法 在编写脚本时,一定要注意空格 基本语法: while [ condition ] do command1 command2 command3 done 1. 2. 3. 4. 5. 6. condition为true时命令1到命令3将会一直执行,知道条件为false ,例如: 1. #!/bin/bash x=1 while [ $x -le 5 ]...
Everyone has a reason for adding a While loop to Bash shell scripts. Looping with a break statement means ending a loop early in a While loop. To use a break statement in a While loop, use this command: This example shows that a While loop is meant to repeat 8 times, but will exit...
Bash while Loop String Comparison The string comparison can be a little tricky using the while loop. In the context of shell scripting the-eqare calledinteger comparison operators. So, these operators cannot be used to compare strings.