Re: Reading portions of large files

[Benjamin Riefenstahl <Benjamin.Riefenstahl@epost.de>]

Hi,


> [attribution cut off]
>     >> head -c2000 bigfile > header-to-be-edited 
>     >> tail -c+2001 bigfile > the-rest
>     >> [...]

> >>>>> "Benjamin" == Benjamin Riefenstahl <Benjamin.Riefenstahl@epost.de>
> writes:
>     Benjamin> This assumes a) Unix, b) that you have the space and
>     Benjamin> time ;-) to deal with the large temporary files.

Lee Sau Dan <danlee@informatik.uni-freiburg.de> writes:
> (b)  is assumed even  if you  use other  method.

With something like the dd method I don't ever have to copy the whole
file.  Makes a difference when your file is a CD image of 600 MB and
all you want to do is patch the partition table.

> Time?  It doesn't take much time to 'split' and 'cat'.

It takes several minutes on my machine with the mentioned file.

> Why not 'split'?

I didn't think of that one before.  But it also copies the whole
file. 

> There are hex editors which doesn't need to load the whole file into
> memory.

I'm not aware of a commonly used hex editor on Unix.  Do you have a
recommendation?


so long, benny