Why doesn't this work?

gistfile1.sh

# this doesn't work
find . -type f -iname '*rhtml' -exec echo git mv {} `echo {} | sed 's/rhtml$/html.erb/i'` \;

# output
..
git mv ./pictures/_form.rhtml ./pictures/_form.rhtml
..

# but this works
find . -type f -iname '*rhtml' | while read i; do echo git mv $i `echo $i | sed 's/rhtml$/html.erb/i'`; done

# output
..
git mv ./pictures/_form.rhtml ./pictures/_form.html.erb
..

Bizarrely the following works, in so far as the manually added trailing 'rhtml' is replaced properly.

find . -type f -iname '*rhtml' -exec echo git mv {} echo {}rhtml | sed 's/rhtml$/html.erb/i' ;

Makes me suspect that echo {} isn't doing what I think it is..

Here's why it doesn't work..

1. The backticks are evaluated by the shell beforehand.

echo {} outputs literal {}

2. "{}" won't match the sed regex "rhtml$" so no substitution takes place

This makes the -exec block: echo git mv {} {}

3. Find runs and replaces the {}s with filenames

Output: git mv ./pictures/_form.rhtml ./pictures/_form.rhtml

I believe the problem is that the backticked expression is evaluated by the shell before the find command is run.

Why you gotta type so quickly?