From: Igal Koshevoy <igal@...>
Date: 2008-06-28T06:55:50+09:00
Subject: Re: changing the shebang of ruby files best way ?

Greg Donald wrote:
> for file in *.rb; do
>   cp $file $file.tmp
>   sed -e "s/#!\/usr\/bin\/ruby\ -w$/#!\/usr\/bin\/env\ ruby\ -w/g"
> $file.tmp >$file
>   rm $file.tmp
> done
>   
Or as sh and Ruby:

for file in *.rb; do
    ruby -p -i.bak -e '$_.sub!(%r{(#!)(/usr/bin/ruby)( -w)?}, 
"\\1/usr/bin/env ruby -w")'  "$file"
done

Or using find and Ruby to recurse the entire tree:

find . -type f -name '*.rb' -exec ruby -p -i.bak -e 
'$_.sub!(%r{(#!)(/usr/bin/ruby)( -w)?}, "\\1/usr/bin/env ruby -w")' {} \;

The "-i.bak" tells Ruby to do in-place replacements and backup originals 
to that file extension.

-igal