iflag/oflag for dd(1)

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

Hello

Linux's dd(1) has iflag and oflag operands to specify the O_* flags that
should be given to open(2) for the input and output file. It works like
this:

dd if=in.txt of=out.txt oflag=direct,sync

That tells out.txt should be open with O_RW|O_DIRECT|O_SYNC

There is the question on how to cope with existing behavior. IMO it
should behave like this:

1) iflag should completely override default O_RDONLY for input open
flags.

2) oflag should only overring O_CREAT in default output open flags:
O_RW | O_CREAT | (ddflags & (C_SEEK | C_NOTRUNC) ? 0 : O_TRUNC))
it should become:
O_RW | oflag | (ddflags & (C_SEEK | C_NOTRUNC) ? 0 : O_TRUNC))
with unspecifield oflag being set to O_CREAT

Anyone against adding the feature? I can craft a patch if it is
desirable.

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu%netbsd.org@localhost