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From: Bart Schaefer <schaefer@brasslantern.com>
Message-Id: <151228171334.ZM20343@torch.brasslantern.com>
Date: Mon, 28 Dec 2015 17:13:34 -0800
In-Reply-To: <56819F48.7000209@gmail.com>
Comments: In reply to Jacek Wielemborek <d33tah@gmail.com>
        "exec format error ignored?" (Dec 28,  9:44pm)
References: <56819F48.7000209@gmail.com>
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To: zsh-workers@zsh.org
Subject: Re: exec format error ignored?
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On Dec 28,  9:44pm, Jacek Wielemborek wrote:
}
} I found that "echo > ~/bin/some_test && some_test" doesn't show me any
} error, but "strace some_test" says that execve failed. How is that?

The shell traps the failed execve and attempts to run the file as a shell
script instead.  This silently succeeds (an empty line is the same as
"true" for shell script purposes).  This is standard for shells. [*]

Conversely "strace" does not have this special-case run-script logic and
reports the failed execve as an error.

[*] All currently released versions of zsh will report an exec format
error on an *empty* file, as opposed to a file containing a single
newline.  This will be fixed in a forthcoming release.