iTerm2 Error – Red Lines and Session Ending Message

erroritermpython

I've been experimenting with threading and running bits of python from iTerm in MacOS yesterday. Today I opened iTerm and two windows opened, one with thick red lines inside it.
I received a Warning message from MacOS:

A session ended very soon after starting. Check that the command in profile “Default” is correct.

I said OK, the window with the red closed immediately, and I quit iTerm.

Question: What is really happening here? I've never seen red lines appear in iTerm2 or a session close immediately upon starting. Is this just "one of those things" or could something be seriously wrong that needs attention?

I only have one profile, called default.

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edit: after coaching in comments, I restarted iTerm2, same red lines. Engaged a second brain cell and realized I can move the error message out of the way, revealing the message in red in the iTerm2 window: Broken Pipe

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Best Answer

I've seen this several times. It's caused by exiting an iTerm window. If you type exit in the window you'll be able to reproduce this behavior. I would check whatever command executes when iterm opens. This is defined in preferences.