[ale] sed

[Danny Cox]

And another old fart weighs in:

On Thu, 2007-05-17 at 21:51 -0400, David Tomaschik wrote:
> Jamey Owens wrote:
> > One note of caution.  It can be pretty dangerous to try and use the same 
> > file for input and output.  Lots of shells will leave you with a totally 
> > empty file using the previous sed command with input & output being equal.
> >
> >   
> Are there any shells capable of handling that structure in the way one
> would expect?  (i.e., acting on the single file without destroying or
> requiring a temporary file to be moved around)

	In "The UNIX Programming Environment", they build up a shell script
named "overwrite", which will do what you want.  The syntax is something
like this:

	overwrite cmd file

and you probably had to quote the command due to redirects, and the
like.  To use the current thread's example, it would look something like
this:

	overwrite 'sed "s/abc/xyz/g" file' file

and it would do the right thing.

	Undoubtedly, there's a replacement script already included, or some
neat bash syntax for doing this sort of thing these days. ;-)

-- 
kernel, n.: A part of an operating system that preserves the
medieval traditions of sorcery and black art.

Danny