#!/usr/bin/env ruby
#!/usr/local/bin/ruby

# Cut just the columns specified.
# usage ruby -s columns.rb -columns=one,two,five [-header=2] [filenames]
# The input must contain a header line.
# This header contains column titles.
# All lines before the header are ignored.
# Eric Blossom - September 2004

header = 1
header = $header.to_i() if $header != nil
columns = ""
columns = $columns if $columns != nil

columnTitle = columns.split( /[,;] */ )
$; = "\t"
while gets

  line = chomp.split()

  next if $. < header

  if header == $.
    iCols = columnTitle.map { |x| line.index( x ) }
    iCols.delete( nil )
  end

  out = iCols.map { |x| line[x] }
  puts out.join( $; ) if ! out.empty?

end