[X-Unix] Remove last ten lines of files

[Stroller]

On Jan 2, 2004, at 11:04 am, Kuestner, Bjoern wrote:

> does anybody have a simple solution to remove the last ten lines of 
> files
> (of variable length).
>
> An alternative solution would be to remove anything from a file that 
> follows
> a signal pattern like "CutHere".
> ...
> Next I considered what I know about sed and grep.
> Again nothing for the task.
> ...Eventually this script or command should be placed into a postfix
> configuration to treat specific mail signatures.

I'm pretty sure this can be done using `sed`, but my research his 
morning indicates it's tricky. Because `sed` is a stream-editor, it 
doesn't normally know ahead of time where the end-of-file is. For this 
reason you have, I think, to use the placeholder function.

My Linux box seems to have a better `info sed` than my Mac (Panther); 
it gives the following examples, apparently for emulating the `tail` 
command:
      #!/usr/bin/sed -nf
      1! {; H; g; }
      1,10 !s/[^\n]*\n//
      $p
      h

The full page is available here 
<http://www.delorie.com/gnu/docs/sed/sed_26.html> - you may find the 
2nd example useful, also.

My question is: do you REALLY want to do this..? If the emails you're 
transforming are, say, from a mailing list for personal use, then all 
well & good, however if the signatures you're removing are from 
corporate emails, then their removal may be questionable. Should the 
emails ever be used in a legal framework then they may be dismissed 
because they have been manipulated, even if it is not your intent to 
edit their main content.

Stroller.