How did this happen?? Git error? Some other fluke?

Every file in this Rails project is duplicated with a -e and again with a -e-e tacked onto the end of it, like the following. It's that way in my GitHub repository too. But I can't figure out how it happened. Any clue? Google searching comes up empty.

-rw-r--r--@  1 usrname  staff   959 Jan  7 02:13 Gemfile
-rw-r--r--   1 usrname  staff   958 Jan  5 01:10 Gemfile-e
-rw-r--r--   1 usrname  staff   958 Jan  5 01:09 Gemfile-e-e
-rw-r--r--   1 usrname  staff  6650 Jan  7 02:13 Gemfile.lock
-rw-r--r--   1 usrname  staff  6650 Jan  5 01:10 Gemfile.lock-e
-rw-r--r--   1 usrname  staff  6650 Jan  5 01:09 Gemfile.lock-e-e
lrwxr-xr-x   1 usrname  staff    18 Jan  5 00:37 README.rdoc -> doc/README_FOR_APP
-rw-r--r--   1 usrname  staff   283 Jan  5 01:10 Rakefile
-rw-r--r--   1 usrname  staff   283 Jan  5 01:10 Rakefile-e
-rw-r--r--   1 usrname  staff   283 Jan  5 01:09 Rakefile-e-e
drwxr-xr-x   6 usrname开发者_JS百科  staff   204 Jan  5 00:37 app
drwxr-xr-x   5 usrname  staff   170 Jan  5 01:10 autotest
drwxr-xr-x  28 usrname  staff   952 Jan  5 01:15 config
-rw-r--r--   1 usrname  staff   173 Jan  5 01:10 config.ru
-rw-r--r--   1 usrname  staff   173 Jan  5 01:10 config.ru-e
-rw-r--r--   1 usrname  staff   173 Jan  5 01:09 config.ru-e-e

The Explanation in Full

The recursive find and replace command

find ./ -type f -exec sed -i 's/string1/string2/' {} \;

works on most linux, but throws an error on mac os x. The following variant runs, but creates the unwanted '-e' backup files.

find ./ -type f -exec sed -i -e 's/string1/string2/' {} \;

This is the actual command that works as expected on mac os x:

find ./ -type f -exec sed -i "" 's/string1/string2/' {} \;

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Git does not do this, nor does Ruby or Rails. There's some script you've ran that has done this. Think back, what did you do before you noticed this?