A replacement for OSX's path_helper
As to the security of this:

if [ -x /usr/local/libexec/path_helper ]; then
  eval `/usr/local/libexec/path_helper`
fi


This runs the path_helper script, which presumably outputs a string, and then the command represented by the output string is run in the local context.  So this initially presumes you trust path_helper to run anything it wants.  I don't think path_helper could much more damage by running something in your shell instead of what it already ran in a sub-shell.