shell-变量-82
Echo输出变量-e 启用反斜杠\t 制表符\n 换行\r 回车\c 不换行#echo –e “\033========================整数比较-gt 大于-lt 小于-ge 大于等于-lt 小于等于-ne 不等-eq 等于#test 8-gt 9#[ 8 –gt 9 ]#echo $?~~~~~~~~~~~~~~~~~~~~~~比较大小#!/bin/bashRead –p “please input two num:” A B[$A –ge $B]&&echo “the max is $A”||Echo “the max is $B”------------#!/bin/bashRead –p “please input two num:” A Bif[ $A –ge $B ]then echo "the max num is $A"else echo "the max num is $B"fi==========================文件属性的检查-b 设备文件-c 字符文件-d 目录文件-e 存在-f 一般文件-g sgid -L 符合连接-r 可读-s 非空-u suid-w 可写-x 可执行~~~~~~~~~~~~~~~~File1 –nt file2 新File1 –ot file2 旧# [ -e rr.test ] 是否存在 rr.test# [ -f rr.test ] 是否是文件# [ ! –s rr.test ] 是否是空的 ~~~~~~~~~~~~~~~~~~~~~~#！/bin/bashIf [ ! –s $I ]Set –x //打开调试开关,会显示详细的执行过程Then “file $I is null”Else Echo “file $I is not null “Fi~~~~~~~~~~~~~~~~~~~~~~~~#！/bin/bashEcho “please input a file name :”Read FUntil [ $F = “q” ];doIf [ ! –s $F ]Then Echo “file $F is null”Else Echo “file $F is not null”FiRead –p “please input a file name :”FDone ~~~~~~~~~~~~~~~~~~~~判断文件属性#!/bin/bashread -p "please input a directory:" DIRfor I in `ls $DIR`;doif[-f $DIR/$I]thenecho -e "\033[31m $I \033[0m is a file;the>elseecho -e "\033[31m $I \033[0m is not a file;the> `du -sh $DIR/$I |awk '{print}'`"fidone 第一列显示大小#du –sh * //对一个目录计算和并按易读方式显示 （h是易读,s对目录计算总和）#du * 显示大小和文件名两列~~~~~~~~~~~~~~~~~~~~~~~~~
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