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From: Peng Yu <pengyu.ut@gmail.com>
To: zsh-users <zsh-users@zsh.org>
Subject: Precedence of operations in [[
Date: Mon, 3 Dec 2018 09:14:30 -0600	[thread overview]
Message-ID: <CABrM6wkOOze2sxpL6j8Ufe7Y+F+7ZF7pkRfXo=TnMNySDn_=cQ@mail.gmail.com> (raw)

Hi,

It seems that there is precedence of the operations in [[. For
example, && is of a higher precedence than ||. I don't find where it
is documented in the man page. Could anybody show me? Thanks.

I see ARITHMETIC EVALUATION discusses precedence. But I don't think it
is for [[.

$ ./main.sh
for x1 in '' x
do
    for x2 in '' x
    do
        for x3 in '' x
        do
            echo "==> $x1, $x2, $x3 <=="
            [[ $x1 || $x2 && $x3 ]]
             echo $?
            [[ $x1 || ($x2 && $x3) ]]
             echo $?
            [[ ($x1 || $x2) && $x3 ]]
         echo $?
        done
    done
done
==> , ,  <==
1
1
1
==> , , x <==
1
1
1
==> , x,  <==
1
1
1
==> , x, x <==
0
0
0
==> x, ,  <==
0
0
1
==> x, , x <==
0
0
0
==> x, x,  <==
0
0
1
==> x, x, x <==
0
0
0

-- 
Regards,
Peng

             reply	other threads:[~2018-12-03 15:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20181203151634epcas1p13aad5853fb952923ce1e124680834647@epcas1p1.samsung.com>
2018-12-03 15:14 ` Peng Yu [this message]
2018-12-03 15:57   ` Peter Stephenson

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