Re: exec command and error checking

[Guido Berhoerster <gber@opensuse.org>]

* Марк Коренберг <socketpair@gmail.com> [2014-01-28 13:16]:
> $ dpkg -l | fgrep dash
> ii  dash                                   0.5.7-2ubuntu2
>                 POSIX-compliant shell
> 
> $ exec 9<no_such_file && echo TEST
> dash: 1: cannot open no_such_file: No such file
> 
> $ exec 9<no_such_file || echo TEST
> dash: 2: cannot open no_such_file: No such file
> 
> So, I cannot test this operation without using $?

No, exec is a special built in and POSIX specifies that
...if a redirection error occurs (see Consequences of Shell
Errors), the shell shall exit with a value in the range 1-125

dash correctly exits with exit status of 2 as it should. ksh93,
mksh, and pdksh do the same.

> in BASH this works as expected (even in sh mode)

That's either a bug or an intended deviation from the POSIX
standard, you'll have to ask on the bug-bash list about that.
-- 
Guido Berhoerster