From: Bart Schaefer <schaefer@brasslantern.com>
To: zsh-users@zsh.org
Subject: Re: if the file is not found the files is not found is the file not found
Date: Sun, 04 Mar 2012 10:37:57 -0800 [thread overview]
Message-ID: <120304103757.ZM24588@torch.brasslantern.com> (raw)
In-Reply-To: <20120304143102.GE18164@solfire>
In-Reply-To: <CAHYJk3TEsrLmhKuoM9dRvM+dW2VM43DTFNaPv1gEt_MEigWXvQ@mail.gmail.com>
On Mar 4, 3:31pm, meino.cramer@gmx.de wrote:
}
} [ -f ${f}-[0-9]*.mp2 ]] && rm -f ${f}-[0-9]*.mp2
This won't work even if the files do exist, because you can't apply
a single "-f" test to the multiple files that result from the glob.
Also you've used "[" on the left but "]]" on the right, which is
mostly nonsense. If you instead used [[ on the left then the glob
would not be expanded and the test would again fail.
On Mar 4, 3:37pm, Mikael Magnusson wrote:
}
} If you setopt extendedglob you can append (#qN) to the pattern
You don't even need extendedglob -- you just need bare_glob_qual, which
is on by default unless you're in sh/ksh emulation modes:
rm -f ${f}-[0-9]*.mp2(N)
I'm sure the archives of zsh-users hold many different answers to the
question, "Given a file pattern, how do I test whether at least one
matching file exists?" Unfortunately, there's really no way to do so
in a single operation unless you set the no_nomatch option. [[ ]]
does not perform globbing, and the test operators such as [ -f ] are
defined to return TRUE rather than FALSE on a *missing* file name
operand, so null_glob is not sufficient.
And yet we've never added a glob qualifier to invert nomatch (nor to
invert bad_pattern) for a single glob ... however, we did invent
anonymous functions, so you can make multiple operations look like a
single operation:
if (){ setopt localoptions no_nomatch; [ -f ${f}-[0-9]*.mp2([1]) ]; }
then rm -f ${f}-[0-9]*.mp2
fi
The "if (){ ... }" does not define a function named "if" because "if"
is a reserved word. The ([1]) qualifier on the end of the pattern
extracts only the first matching file so that you aren't passing too
many arguments to "[ -f ... ]".
If you don't like that syntax and don't mind an extra process, you can
also do this with a subshell:
if ( setopt no_nomatch; [ -f ${f}-[0-9]*.mp2([1]) ]; )
then rm -f ${f}-[0-9]*.mp2
fi
Woof woof.
--
Barton E. Schaefer
next prev parent reply other threads:[~2012-03-04 18:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-04 14:31 meino.cramer
2012-03-04 14:36 ` Moritz Bunkus
2012-03-04 14:37 ` Mikael Magnusson
2012-03-04 18:37 ` Bart Schaefer [this message]
2012-03-04 18:48 ` Mikael Magnusson
2012-03-04 19:44 ` Bart Schaefer
2012-03-04 20:13 ` Mikael Magnusson
2012-03-04 21:47 ` Bart Schaefer
2012-03-05 0:48 ` Mikael Magnusson
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