portdowngrade and meta ports

[RW]

On Thu, 24 May 2012 22:43:08 +0100
Chris Rees wrote:


> For the archive-- just thought-- even though I did a typo there,
> DON'T use:
> 
> mv file file.bak && echo something > file
> 
> at least with csh, file will be clobbered before mv gets to it....

I tried that in bash and csh and it worked correctly in both. 

e.g. in csh:

  %echo nothing > foo
  %mv foo bar && echo something > foo
  %cat foo
  something
  %cat bar
  nothing

If a shell supports short-circuiting then mv must complete before echo
can start, so I don't see how it can fail unless the shell opens the
file before it runs mv.

Are you perhaps mixing this up with what happens with:

 cat foo bar > foo