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Date:   Tue, 16 Mar 2021 20:51:31 +1100
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     rong.a.chen@intel.com, lkp@intel.com, oberpar@linux.ibm.com,
        akpm@linux-foundation.org, kbuild-all@lists.01.org,
        linux-kernel@vger.kernel.org
Subject: Re: [kbuild-all] Re: [PATCH] gcov: fail build on gcov_info size
 mismatch
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Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> See:
> 
>   [torvalds@ryzen ~]$ a="!" [ "$a" = ".size" ]
> 
> is fine, but
> 
>   [torvalds@ryzen ~]$ a="!" [ $a = ".size" ]
>   -bash: [: =: unary operator expected

This isn't doing what you think it's doing.  The first assignment
to a is not in effect when the shell is expanding $a so what you're
actually running is

	a="!" [ = .size ]

Which is why it bombs out.

To get the desired result you need a semicolon:

$ a="!"; [ $a = ".size" ]
$ 

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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