PHWinfo - Afficher un message - testing files for read errors by copying to /dev/null

27/03/2008, 18h05

On Mon, 24 Mar 2008 19:41:35 -0500, James Michael Fultz <xyzzy@sent.as.invalid> wrote:
>* Charles Russell <NOSPAM@bellsouth.net>:
>> James Michael Fultz wrote:
>>> $ find /cygdrive/d -type f -exec cp -v {} /dev/null \;
>>>
>>
>> That yields the error message:
>> cp: cannot create regular file `/dev/null': Invalid request code
>>
>> I don't know whether this is typical unix behavior or something peculiar
>> to Cygwin, which is usually a pretty close emulation. As noted in my
>> original posting, cp does not like /dev/null.

>My thought is that it is a pecularity of Cygwin since it worked when I
>tested on Linux.

>Your cp command lines seemed to fail for different reasons which are
>also failures on Linux. It is possible to copy a single file onto
>'/dev/null' which is itself a file, but it is not possible to copy
>directories onto '/dev/null' as the '-r' would require cp to do.

if you want to check that the file were copied properly, just copying from
the disk to the bitbucket is isn't going to be much . It only show that
the block checksums didn't have fatal errors. You can still have a ton
of data errors that won't be detected.

Either do an md5sum on both source and target files, or do a full comparison
between the source and target files. In linux, the diff command has a '-r'
option to check subdirectories recursively. (my solaris box has the same
option; cygwin which is mostly gnuish should have the same option)

27/03/2008, 18h05	#12
AZ Nomad Messages: n/a Hébergeur:	Re: testing files for read errors by copying to /dev/null On Mon, 24 Mar 2008 19:41:35 -0500, James Michael Fultz <xyzzy@sent.as.invalid> wrote: >* Charles Russell <NOSPAM@bellsouth.net>: >> James Michael Fultz wrote: >>> $ find /cygdrive/d -type f -exec cp -v {} /dev/null \; >>> >> >> That yields the error message: >> cp: cannot create regular file `/dev/null': Invalid request code >> >> I don't know whether this is typical unix behavior or something peculiar >> to Cygwin, which is usually a pretty close emulation. As noted in my >> original posting, cp does not like /dev/null. >My thought is that it is a pecularity of Cygwin since it worked when I >tested on Linux. >Your cp command lines seemed to fail for different reasons which are >also failures on Linux. It is possible to copy a single file onto >'/dev/null' which is itself a file, but it is not possible to copy >directories onto '/dev/null' as the '-r' would require cp to do. if you want to check that the file were copied properly, just copying from the disk to the bitbucket is isn't going to be much . It only show that the block checksums didn't have fatal errors. You can still have a ton of data errors that won't be detected. Either do an md5sum on both source and target files, or do a full comparison between the source and target files. In linux, the diff command has a '-r' option to check subdirectories recursively. (my solaris box has the same option; cygwin which is mostly gnuish should have the same option)