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Date:      Mon, 25 Sep 2006 10:58:39 -0500
From:      Dan Nelson <>
To:        Arindam <>
Subject:   Re: Korn Shell [[ ... ]] operator
Message-ID:  <>
In-Reply-To: <>
References:  <>

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In the last episode (Sep 25), Arindam said:
> I know csh is the shell of choice on FreeBSD. But I have this question
> on Korn Shell and it would be great if somebody could explain.
> Can someone tell me a little more about the Korn Shell [[ ... ]]
> double-brackets construct used for comparing string expressions. How
> does it differe from the standard [ ... ] single brackets.

Different comparison operators, basically, and faster than [ because it
doesn't have to fork /bin/[ .
> You could tell me to RTFM but I haven't gleaned enough clarity from
> such efforts already expended.

They're all documented in the manpage ("ksh93" for the shells/ksh93
ports), under Conditional Expressions.  Compare them with the "test"
manpage.  It looks like FreeBSD's test command does most of what ksh
does, except for the wildcard matching of =, which is handy but can be
emulated with a case statement :)

	Dan Nelson

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