UsrMove feature (was Re: FESCo meeting minutes for 2011-10-24)

[Richard W.M. Jones]

On Tue, Oct 25, 2011 at 08:33:28PM +0200, Michał Piotrowski wrote:
> 2011/10/25 Chris Adams <cmadams at hiwaay.net>:
> > Once upon a time, Michał Piotrowski <mkkp4x4 at gmail.com> said:
> >> I created feature page
> >> https://fedoraproject.org/wiki/Features/F18MorePortableInterpreters
> >
> > I strongly object to this "feature".  /bin/sh is a Unix standard back to
> > IIRC around 7th Edition, and there is NO good reason to break it.  The
> > "#!/usr/bin/env foo" suggested replacement has always been a hack to
> > work around broken systems, not something suggested for all scripts.
> 
> What is wrong with
> #!/usr/bin/env interpreter
> from technical POV?

This is what's wrong:

  $ cat > sh.sh
  #!/bin/sh
  $ cat > env.sh
  #!/usr/bin/env sh
  $ chmod +x sh.sh env.sh
  $ time for i in $(seq 1000); do ./sh.sh; done
  
  real		  0m2.737s
  user		  0m0.750s
  sys		  0m1.519s
  $ time for i in $(seq 1000); do ./env.sh; done
  
  real		  0m3.677s
  user		  0m1.013s
  sys		  0m2.296s

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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