1.8 KiB
1.8 KiB
DD 命令说明
1.一般使用
# 不固定长度，读到文件结尾自动停止
dd if=\<in file name\> of=/dev/\<out file name\> bs=4M status=progress
# 指定长度（4Mx1024=4G）
dd if=\<in file name\> of=/dev/\<out file name\> bs=4M count=1024 status=progress
2.指定 Flag
# iflag 指定 input flag
# iflag 指定 output flag
dd iflag=direct,nonblock if=\<in file name\> oflag=direct,nonblock of=/dev/\<out file name\> bs=4M status=progress
多个 Flag 之间可以用逗号分割，含义如下表。
| Flag | Description |
|---|---|
| append | append mode (makes sense only for output; conv=notrunc suggested) |
| direct | use direct I/O for data |
| directory | fail unless a directory |
| dsync | use synchronized I/O for data |
| sync | likewise, but also for metadata |
| fullblock | accumulate full blocks of input (iflag only) |
| nonblock | use non-blocking I/O |
| noatime | do not update access time |
| nocache | Request to drop cache. See also oflag=sync |
| noctty | do not assign controlling terminal from file |
| nofollow | do not follow symlinks |
| count_bytes | treat 'count=N' as a byte count (iflag only) |
| skip_bytes | treat 'skip=N' as a byte count (iflag only) |
| seek_bytes | treat 'seek=N' as a byte count (oflag only) |