function numbers2csv
    set argn (count $argv)
    if test $argn -gt 2 -o $argn -eq 0
        echo "*** Usage: numbers2csv <file> [<output-file>]"
        return -1
    end
    
    set inputPath (path resolve $argv[1])
    #set exportPath (path change-extension csv $inputPath)
    
    if test $argn -eq 2
        set exportPath (path resolve $argv[2])
    else
        set exportPath (mktemp)
        #trap "rm -f $exportPath" 0 2 3 15 #doesn't seem to work
    end
    
    set applescript "
        set inputPath to \"$inputPath\"
        set exportPath to \"$exportPath\"
        set inputFile to POSIX file inputPath
        set exportFile to POSIX file exportPath
        
        tell application \"Numbers\"
            set theDocument to open inputFile
            delay 1
            export theDocument to exportFile as CSV
            close theDocument
        end tell
        "
    
    osascript -e $applescript
    
    if test $argn -eq 1
        cat $exportPath
        rm -f $exportPath
    end
end