[RLUG] quick question

[Sebastian Smith]

I'm with Brian on this one.  I don't know of a way to truncate a file 
without playing with the filesystem.

- Sebastian


On Wed, 28 Jun 2006, Brian Chrisman wrote:

> I kind of doubt that there's anything else you can do.  I think you'd have to 
> have some program that manipulates the the filesystem inodes to do what you 
> want.  Generally you are limited to the system call interface like 'open', 
> 'read', 'write', 'truncate'.. and all that stuff.
> You could certainly write null characters over the first 300 lines, but if 
> that doesn't do what you want, I'm not certain what else will, barring some 
> sort of hacky work with a filesystem debugger tool.
>
> You could also have some part of your program which maintains a current 
> offset into the file, and automatically does a 'seek' to that position when 
> you next run it... it'd be a dirty hack, but it might be what you want.  Then 
> you'd have to write your code in some full programming language, not sed.
>
> -Brian
>
>
> Grant Kelly wrote:
>> Alright unix fans, who can answer this the best?
>> 
>> I have a text file, it's about 2.3 GB. I need to delete the first 300
>> lines, and I don't want to have to load the entire thing into an
>> editor.
>> 
>> I'm trying `sed '1,300d' inputfile > output file`  but it's taking a
>> long time (and space) to output everything to the new file.
>> 
>> There has got to be a better way, a way that can do this in-place...
>> 
>> 
>> Grant
>> 
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