用shell脚本写出检测/tmp/size.log文件，如果存在显示它的内容，不存在则创建一个文件将创建时间写入

 1 #!/bin/bash
 2 if [  -d "/tmp" ]; then
 3 echo "/tmp is exists"
 4 else
 5 mkdir /tmp
 6 fi
 7 if [  -f "/tmp/size.log" ]; then
 8 echo "size.log is exist";cat /tmp/size.log
 9 else
10 touch /tmp/size.log; date > /tmp/size.log; echo "date has been successfully  written to size.log"
11 fi