一、简介
二、实例
1）复制二进制文件指定章节
dd if=managerd skip=685632 iflag=skip_bytes bs=829 count=1 of=test
2）修改二进制文件指定章节
dd if=ca.pem seek=685632 oflag=seek_bytes bs=829 count=1 of=managerd
3）复制系统
https://major.io/2010/12/14/mounting-a-raw-partition-file-made-with-dd-or-dd_rescue-in-linux/