cut -b on huge files

[Klein, Roger]

Hi,
 
I am using cut in an awkward situation: I got huge files that for any
reason show larger file sizes than they actually have.
 
For instance:
# stat boot_image.clone2fs
  File: `boot_image.clone2fs'
  Size: 1077411840      Blocks: 113480     IO Block: 4096   regular file
Device: 902h/2306d      Inode: 2845250     Links: 1
Access: (0600/-rw-------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2008-10-08 16:29:55.066038214 +0200
Modify: 2008-10-08 16:43:10.000000000 +0200
Change: 2008-10-08 16:43:10.000000000 +0200

If you compare the apparent size (also shown by ls) with the size that
results from the number of blocks times 512 bytes you see what I mean.
 
'du' reports the correct sizes b.t.w.:
# du -k boot_image.clone2fs
56740   boot_image.clone2fs

Now I found a hint on the Web
(http://www.programmersheaven.com/mb/linux/187697/245244/re-how-to-chang
e-filesize-in-linux/?S=B20000) for how the change the incorrect filesize
by using cut to take over only a given amount of bytes into a new file:
cut -b 1-500 oldFile > newFile
 
I never tried it on short files, but when I use this on the above file I
get a very different result than expected:
# cut -b 1-58101760 boot_image.clone2fs > boot_image.clone2fs_correct
# stat boot_image.clone2fs_correct
  File: `boot_image.clone2fs_correct'
  Size: 309987280       Blocks: 606048     IO Block: 4096   regular file
Device: 902h/2306d      Inode: 2469155     Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2008-10-08 16:31:20.000000000 +0200
Modify: 2008-10-08 16:31:38.000000000 +0200
Change: 2008-10-08 16:31:38.000000000 +0200

The number of blocks and the apparent size is all but correct now. To me
this looks like a typical overflow problem. Could you please investigate
this?
 
Regards,

Roger Klein
Finanzrechenzentrum der OFD Magdeburg
Otto-von-Guericke-Str. 4
39104 Magdeburg
Tel: +49 391 545-3868
Fax: +49 391 545-3873
!!NEU!! E-Mail: address@hidden