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  • shell编程的for和while循环

    1. for循环

      语法1:for NAME [in WORDS ... ] ; do COMMANDS; done

    #!/bin/bash
    if
    [[ $# -lt 1 ]] ; then echo no param!!!; exit; fi for a in "$@" ; do echo hello$a > ${a} ; done

    如果参数的个数小于1,直接退出。否则把hello+参数名依次重定向到参数名作为文件名的文件。

    $@:命令行所有的参数

      语法2:for (( exp1; exp2; exp3 )) do COMMANDS; done

    for (( a=1 ; a  < 11 ; a = a + 1 )) ; do echo $a ; done

    循环打印1到10

    2while循环

      语法1:while COMMANDS; do COMMANDS; done

      语法2: (( exp1))

          while (( exp2 )) ; do

            COMMANDS

            (( exp3 ))

          done

    #!/bin/bash
    (( count = $# ))
    (( a = 1 ))
    while (( a <= count )) ; do
        echo $1;
        shift;
        (( a = a+1 ))
        done

    循环打印命令的参数

    $#:命令的参数个数;

    shift:参数左移一位

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  • 原文地址:https://www.cnblogs.com/fireinthehole/p/10088886.html
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