2018-02-14 15:24:40 +08:00
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#!/bin/bash
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# shell 的常用语法
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# for 循环
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for item in `ls`;
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do
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echo ${item} ;
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done
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2018-02-14 15:37:05 +08:00
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# 数字for循环
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for((i=1;i<=10;i++));
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do
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echo $(expr $i \* 3 + 1);
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done
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2018-02-14 15:24:40 +08:00
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# 判断文件夹是否存在
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if [ ! -d "/data/" ];then
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mkdir /data
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else
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echo "文件夹已经存在"
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fi
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# 判断文件是否存在
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if [ ! -f "/data/filename" ];then
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echo "文件不存在"
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else
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rm -rf /data/filename
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fi
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2021-02-23 20:34:32 +08:00
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# 循环判断pid是否还活着
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while kill -0 $PID; do
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sleep 1
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done
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2018-02-14 15:24:40 +08:00
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# 常见的判断
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# -e filename 如果 filename存在,则为真 [ -e /var/log/syslog ]
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# -d filename 如果 filename为目录,则为真 [ -d /tmp/mydir ]
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# -f filename 如果 filename为常规文件,则为真 [ -f /usr/bin/grep ]
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# -L filename 如果 filename为符号链接,则为真 [ -L /usr/bin/grep ]
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# -r filename 如果 filename可读,则为真 [ -r /var/log/syslog ]
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# -w filename 如果 filename可写,则为真 [ -w /var/mytmp.txt ]
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# -x filename 如果 filename可执行,则为真 [ -L /usr/bin/grep ]
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# filename1-nt filename2 如果 filename1比 filename2新,则为真 [ /tmp/install/etc/services -nt /etc/services ]
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# filename1-ot filename2 如果 filename1比 filename2旧,则为真 [ /boot/bzImage -ot arch/i386/boot/bzImage ]
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