Comment 9 for bug 1468832

That error dialog is supposed to be helpful. ;) It was implemented (by me) as a fix of bug #678421, which was originally filed as a bug about GDM and Xsession, and one idea is to *prevent* that errors are silently ignored.

On 06/26/2015 12:58 AM, Derek Martin wrote:
> if you don't care to fix this,

I'm not in a position to decide on it.

> what's your proposed fix for lightdm barfing on errors from terminal
> commands that quite rightly belong in .profile?

Maybe state that certain commands should only be executed in case of an interactive shell. This Ask Ubuntu answer might give you a hint:

http://askubuntu.com/questions/592839