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Re: Combination of "eval set -- ..." and $() command substitution is slo


From: Robert Elz
Subject: Re: Combination of "eval set -- ..." and $() command substitution is slow
Date: Tue, 16 Jul 2019 00:49:07 +0700

    Date:        Wed, 10 Jul 2019 17:21:00 +0000
    From:        astian <address@hidden>
    Message-ID:  <address@hidden>

I doubt it makes any difference to the timing, which I think
Chet has already answered, but it is worth pointing out that these
two commands ...

                        printf '%s\n' "`printf %s "$i"`"
                        printf '%s\n' "$(printf %s "$i")"

which (I believe)) are supposed to be the same thing, using the
different (ancient, and modern) forms of command substitution aren't
actually the same.   In the first $i is unquoted, in the second it is
quoted.   Here, since its value is just a number and IFS isn't being
fiddled, there is not likely to be any effect, but if you really
want to make those two the same, the first needs to be written as

                        printf '%s\n' "`printf %s \"$i\"`"

Such are the joys of `` command substitutions (just avoid them).

kre




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