Shell if 结构.md

「 Shell if 结构 」

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💬 格式

if 条件测试
    then
    条件为真时的命令
    else
    条件为假时的命令
fi

💬 举例1

#!/bin/bash
#命令执行后返回值为0，报告命令执行成功
#否则报告出错
true
if (($?==0))
then
    echo "command was successful."
else
    echo "An error was encountered"
fi

💬 举例2

#!/bin/bash
read answer
if (($answer==0))
then
    echo "command was successful."
else
    if (($answer==-1))
    then
        echo "An error -1 was encountered."
    else
        echo "An other error was encountered."
    fi
fi

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