[EMAIL PROTECTED] wrote: > Bad news fellows, regarding: > > `-u' > `--update' > Do not copy a non-directory that has an existing destination with > the same or newer modification time. If time stamps are being > preserved, the comparison is to the source time stamp truncated to > the resolutions of the destination file system and of the system > calls used to update time stamps; this avoids duplicate work if > several `cp -pu' commands are executed with the same source and > destination. > > Well it just so happens that the resolution on all(?) vfat flash > cards, is TWO seconds, > > $ w3m -dump http://en.wikipedia.org/wiki/File_Allocation_Table | grep 2\ sec > Note that the seconds is recorded only to a 2 second > > $ cd some/directory/on/my/vfat/flash_card > $ stat *|perl -nwe 'm/^Modify:.*(\d\d)\.000/&&print " $1"'; echo > 04 02 02 02 24 04 04 58 00 24 16 58 58 02 34 > --all TWO seconds, (so they are always even numbers above.) > > This means that > set /non-vfat/file /vfat/file > $ cp -p $1 $2 #if done during an odd-numbered second of time, > $ cp -u $1 $2 #will cause this second line to wastefully fire again. > > So please investigate your claim that > the comparison is to the source time stamp truncated to > the resolutions of the destination file system > I bet that you never dreamed that you had to consider more than > one second vs. fractional second differences.
Yes, it's unfortunate that FAT does not allow for higher resolution st_mtime, like it does for creation time. Yet another reason to avoid FAT, whenever possible. It'd be great if you would suggest wording to document this discrepancy. _______________________________________________ Bug-coreutils mailing list Bug-coreutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-coreutils