Re: check for existence without full globbing

["Bart Schaefer" <schaefer@brasslantern.com>]

On Feb 3, 10:29pm, Le Wang wrote:
}
} I need to get a list of directories that have .java files in them.  Here is
} the snipplet:
} 
} for i ( $sourcePath ) {
}   for j ( $i/**/*(-/) ) {

The (-) qualifier there probably doesn't do what you think.  **/ won't
descend through symlinks, so **/*(-/) will not descend beyond the first
symlink in any path.  Hence you'll only find the .java files that are
directly within the symlinked directories, not those in any subdirs of
the symlinked directories, if you see what I mean.

If you can be sure the symlinks don't cycle, you can use ***/ instead.

}     setopt localoptions
}     setopt nullglob
}     unsetopt globsubst
}     tempArr=( $j/*.java )
} 
}     if (( $#tempArr >= 1 )); then
}       temp=${j#$i/}
}       temp=${temp//\\//.}
}       packages=( $packages $temp )
}     fi
}   }
} }
} 
} It was taking quite a while to glob through all the .java files.

I'll bet it's taking much longer to do the ${j#$/} ${temp//\\//.} stuff,
plus packages=( $packages $temp ), in a loop, than to do the globbing.
And you should almost never put setopt/unsetopt commands inside a loop
body, because they don't revert at the end of the loop (only at the end
of a shell function), so all you're doing every time around is resetting
something that's already set.

Try this and see if it's faster:

    typeset -U packages
    packages=( ${~~^sourcePath}/./**/*(N-/) )
    packages=( ${~~^packages}/**/*.java(N:h) )
    packages=( ${${~~packages##*/./}:gs,/,.} )

The double tildes in ${~~...} turn off globsubst for that expansion, and
the N turns on nullglob, so you don't have to mess around with setopt.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Zsh: http://www.zsh.org | PHPerl Project: http://phperl.sourceforge.net