Help Handling CSV Columns

[fightoplankton]

I have been struggling for days on just the first part of this script.
Please help! I need to add the ability to delete the last column of each
csv, which vary in their lengths.

require 'rubygems'
require 'roo'
require 'fileutils'
require 'rio'

FileUtils.mkdir_p "/Users/pshapiro/Desktop/Excel/xls"
FileUtils.mkdir_p "/Users/pshapiro/Desktop/Excel/tmp"
FileUtils.mkdir_p "/Users/pshapiro/Desktop/Excel/csv"

@filesxls = Dir["/Users/pshapiro/Desktop/Excel/*.xls"]
for file in @filesxls
	FileUtils.move(file,"/Users/pshapiro/Desktop/Excel/xls")
end

@filesxls = Dir["/Users/pshapiro/Desktop/Excel/xls/*.xls"]
@filetmp = Dir["/Users/pshapiro/Desktop/Excel/xls/*.xls_tmp"]

for file in @filesxls
	convert = Excel.new(file)
	convert.default_sheet = convert.sheets[0]
	convert.to_csv(file+"_tmp")
end

@filestmp = Dir["/Users/pshapiro/Desktop/Excel/xls/*.xls_tmp"]

for file in @filestmp
	FileUtils.move(file,"/Users/pshapiro/Desktop/Excel/tmp")
end

dir = "/Users/pshapiro/Desktop/Excel/tmp/"  
files = Dir.entries(dir)  
files.each do |f|  
next if f == "." or f == ".."  
oldFile = dir + "/" + f 
newFile = dir + "/" + File.basename(f, '.*')  
File.rename(oldFile, newFile)  
end 

files = Dir.entries(dir)
files.each do |f|  
next if f == "." or f == ".."  
oldFile = dir + "/" + f 
newFile = dir + "/" + f + ".csv"
File.rename(oldFile, newFile)  
end 

@filescsv = Dir["/Users/pshapiro/Desktop/Excel/tmp/*.csv"]

for file in @filescsv
	FileUtils.move(file,"/Users/pshapiro/Desktop/Excel/csv")
end

FileUtils.rm_rf("/Users/pshapiro/Desktop/Excel/tmp")

@filescsv = Dir["/Users/pshapiro/Desktop/Excel/csv/*.csv"]

for file in @filescsv
	5.times {
	text=""
	File.open(file,"r"){|f|f.gets;text=f.read}
	File.open(file,"w+"){|f| f.write(text)}
	}
end

rio("/Users/pshapiro/Desktop/Excel/csv/Attention.csv").csv.skipcolumns(1..2) > rio('/Users/pshapiro/Desktop/Excel/csv/Attention_Fixed.csv').csv(',')

Thanks!